The Grey Nayr wrote...
So the truth is that you just don't like what you learn. That the Reapers' purpose is abstract and you don't agree with it.
Nah, that would be implying that I think there is some validity to the information the Catalyst provides, that the story simply went in a direction I disliked. I've experienced stories like this. Mass Effect 3's ending is not one of them.
Quite simply, I find the Catalyst's information substandard, from both an in-universe perspective and a narrative perspective.
But the Reapers implied that as early as the first game. And even if preventing a technological singularity wasn't the original idea, the original idea(dark energy) was just as abstract.
Sovereign said "We are the end of everything", "We are the apex of evolution", "We are each a nation", and "You exist because we allow it, you will end because we demand it".
Later it was revealed that the Reapers are races/nations of people whose transapience was uploaded into a single construct, and that the Reapers' purpose is to allow primitive life to exist(you exist because we allow it) by preventing synthetics from destroying them, which requires removing advanced civlizations(you end because we demand it).
I do not take issue with this.
Harbinger said "That which you know as Reapers are your salvation through destruction". Which was later proved to be true from their perspective. They don't see organics as individuals, and harvesting some and allowing others(primitives) to exist ensured that organic life in general was preserved.
I do not take issue with this.
Everything the Catalyst said was consistent and clarifying with what Sovereign and Harbinger(the only Reapers you've gotten to speak too prior to ME3) said.
I took issue with neither of your previous paragraphs.
And the conflict with synthetic life is true enough as well. You don't like it, you might argue that it's not 100% certain that synthetics will always beat organics, but nearly every time in the series that you've crossed synthetic life, you'd had to fight it.
The same could be said for organics. How many anonymous organics does Shepard murder over the course of the trilogy?
Already this reveals a far better motive for the Catalyst: stopping all conflict. Period. This is something which works far better as a theme, because it relates to every conflict which Shepard has ever dealt with, not a minor subset.
The threat of synthetics suddenly elevates to the forefront a conflict which had previously only been a subplot. Synthetics are the main threat, despite the fact that organics have seen themselves almost destroyed quite a few times by their own hands, no less. Hell, Krogan rebellions. Rachni Wars. First Contact War. Hell, our own World War II. We're likely to die by our own organic hands, let alone synthetics. As a motive, this would take into account everything Shepard does throughout the series: Genophage, Rachni, sidequests, whatever.
And it's a simple logic that you can't count on every synthetic race to be as fallible as the Geth or as reasonable as them and EDI(the Zha'til from Javik's time sounded pretty ruthless). And just because you can destroy the geth doesn't mean that future generations will able to defeat the next flock of synthetics to evolve out of control.
As above, you could say the same for any race. Would you like to declare war on the Krogan, the Batarians, or the Turians first? We don't know whether future generations will eventually have the power to destroy us.
And the fact that Organics and Syntheitcs are nearly destined to fight with each other at some point was clear as early as Mass Effect 1.
You're right. That's why ME2 and 3 both went out of their way to set EDI and the Geth up as organic allies to dispute the belief that synthetics and organics can't get along. But hey, we're right back at Organics vs. Synthetics.
This would be like taking Episode VI Luke Skywalker and in the last ten minutes reverting him back to little farm boy Luke. The narrative has built up an entirely different focus, much like how character development works.
ME1 began with: organics and synthetics can never get along. ME2 brought complexity to the equation with: hey, Synthetics can be trusted and prove their worth. ME3 (until the last ten minutes) continued with showing how synthetics and organics can cooperate, especially in scenarios where you either choose the Geth or force cooperation. Not to mention, EDI's acceptance into the crew.
So just because you don't like what it has to say doesn't make it wrong. That's reality, the world isn't what you want it to be and it's seldom understandable why it is the way it is.
If Bioware wanted to go that route, they should have kept EDI and the Geth as one dimensional villains. From a narrative perspective alone, it fails.
You expected the Catalyst to either be a true villain with malicious intent, or to have a reason for what it does that's genuinely understandable. But its conclusions are its own and it believes it is right, just like pretty much every person that's ever existed.
No, I expected reasoning founded in logic. Some advice: I'll tell you what I expected, not the other way around.

If we're going down the "everyone believes they're right" argument, the Reapers' motives could have been that they execute organics every 50k years in order to steal their underpants. The Reapers reasoning being impossible to understand we can't comprehend why they do what they do.
In other words: The writers can include any number of asinine motives for the Reapers, on the grounds that we can't comprehend them. That doesn't make any of those million and one motives sensible. If the Catalyst's goal was simply to preserve organic life, there were about a million and one ways to do it which are infinitely more effective (and straightforward) than purposely allowing organics to reach a point where they pose a threat to the Reapers (however small).
But it's opinion changes based on Shepard. If you do well, you impress the Catalyst enough to make him reconsider his stance(you have altered the variables = quite an apt description considering machines think with arithmetic), and if you don't do well(low EMS), he looks down on you and plainly refuses to help you(the crucible changed me, created new possibilities, but I can't make them happen, and I won't)
Don't get me started on the whole impressing the Catalyst point. If the Catalyst was impressed, the dynamic of the conversation would have changed. Apparently, it's okay for me to Destroy the Reapers, but the Catalyst couldn't take it upon itself to give up the genocide. Very odd reasoning.
Rather than you assuming my arguments for me, I'll outline a few of my own:
1) the Catalyst fails in comparison to Vigil. As another user pointed out, the Catalyst's mere appearance causes problems. Considering he makes his home on the Citadel, this already raises the wonderful issue of: what the hell did he need Sovereign for? Or the Keepers? He could have opened the relay whenever he chose. And the solution was simple: have the Catalyst appear to you, much like Sovereign or Harbinger were able to, but keep him a manifestation of the Reapers' intelligence. There was absolutely no purpose to making him a part of the Citadel, aside from throwing questions at ME1's plot.
On this level alone, Vigil works better. He's a simple computer on a remote planet.
2) As an information source, Vigil functions far better. Again, as another user pointed out, Vigil does not exist to provide further conflict to the story. Vigil provides clarification and resolution. He puts in context all the different elements of the story which the player already had questions regarding: what is the Conduit? as an example.
The Catalyst does not do this. He not only introduces new information, he attempts to place the story inside an entirely new framework. Suddenly, Mass Effect isn't about the Reaper threat, the Catalyst is telling us. It's about this Organic Synthetic battle, which we were never worried about. But the story still forces you to make a moral decision on those grounds, without even providing the proper framework for the player to believe the Catalyst. He doesn't elaborate on the differences between man and machine or provide exposition.
We're not given the option to argue, inquire, or debate in the manner which Shepard has throughout the series. Instead, the Catalyst exists to help us solve a previously non-existent problem. This would be like Episode VI introducing global warming in the last five minutes and telling us that Palpatine is not evil, he needs the Empire's resources to stop the Sun from killing everyone.
3) The nature of exposition
One criticism I have often framed at Bioware and specifically Vigil is that he is an exposition dump. Sovereign is minutes away from galactic genocide and Vigil is busy explaining (in very unnecessary detail) all the different elements of the Prothean extinction.
The Catalyst is the opposite problem and far worse. As he introduces an entirely new conflict, we needed far more exposition and detail than Vigil gave us before his conflict will be accepted as true. Vigil announced himself as an ally character. The Catalyst announces himself as provoker of said genocide. We need halfway decent dialogue, which the original did not give us and is only slightly better than the EC. Comparing the Reapers to some cleansing fire was not a good idea, for example. Most Bioware games go out of their way to place their plot twists in context. ME3 fails to effectively do this.