As for the last two major Bioware games, while I get the dissatisfaction that resulted from DA2 (again, which I chalk up to a rushed release), I will never fully understand the reaction to ME3. Sure I disliked the endings, but the overall experience (save the somewhat lame package-quests) was great. Indeed, I recall the earlier posts folks made about ME3 and they were incredibly positive. It wasn't until we reached the end that the internet exploded and people acted as though their families were murdered. In short, the most vulgar critics tend to overstate matters and froth emotionally without the ability to compartmentalize, and in turn infect other similarly minded people.
I don't really believe in the idea of people infecting others with views, because I don't think anybody is compelled to agree with something they don't already agree with or wouldn't agree with if presented that view. I don't consider discourse "infecting," even if not done in the way you'd prefer. You simply need to present an alternate viewpoint to counteract theirs, if you care about the general forum-goer's opinion (which I try not to).
As for the criticisms of DA2, I think that the enemy spawning, difficulty imbalances, repeating levels, shift to potion-based healing, narrative structure (time jumps and disjointed acts), and plot weirdness (being attacked by mages and accused of being pro-templar despite making every decision pro-mage up to that point, or every mage/templar being basically evil except for 3 or 4, etc.) were all really bad. I think the Arishok portion of the plot was excellent. I think the companions were mostly just tropes, particularly Isabella (Varric is an exception). I shouldn't so vehemently dislike the companions the way I did. The part where I'm slaughtering a Dalish clan on behalf of a person I don't even like is not a game experience I need to have. I liked the new mage animations, but not the other combat animations. I didn't like that side quests were the first 15 hours of the game instead of actually being on the side. The Anders event was bad, and when I said "I don't want to take a side" and she said "YOU HAVE TO" for a conflict I didn't want any part of, I literally turned off the game. I then booted it on easy to see the end, and never looked back.
ME3's plot was flawed from the get-go, and I noticed it immediately. I was one of the first people criticizing the game's ending on this forum and clearly remember when everyone was singing its praises. I didn't particularly understand it then or now. The points system was really annoying. The impact of the vital choices were nullified by a too-powerful paragon/renegade system. Many of the choices they teased as being important (collector base/rachni, etc.) didn't pan out. The Crucible made no sense from the beginning, as the Prothean VI on Ilos would've mentioned it had the series been fully planned out instead of an ending being shoehorned in because of Drew Karpshyn's absence. Also, as a concept the Crucible makes no sense. All these races combine to build something they don't know the end-result of, throughout all of time, and it requires the Citadel to work despite the Citadel always being the first place that gets taken by the Reapers. The death of companions gets nullified in impact because they simply get replaced by very similar people of the same race. The gameplay wasn't great compared to other 3rd person shooters (even Gears 1 from 5 years prior), there were noticeably high levels of auto-dialog, and the Prothean companion's effect on the plot was extremely disappointing plot-wise. There were also too many bugs, some that prevented quests from popping up or finishing. It had fun parts, but not enough to make up for all that. And that doesn't at all mention the end (which I purposefully neglected to mention, and enraged me more for its multiplayer requirement than anything).
The vulgarity comes because people have the ideas in their head of what makes them mad, but they're too stupid more often than not to explain it. Or, they don't want to take the time to explain it. I don't think it's problematic so much as it is lazy. I don't blame them for it, but it does annoy me sometimes. The real problem is that BioWare seems to repeatedly make statements which can be taken out of context in such a fashion, as they often are combative. I felt hostility by the BioWare staff leading up the DA2 release, to the point where I thought my critiques must have been really false. I'm sure to them that I was only one in a sea of vulgar people, but I wasn't using vulgarity (or at least I hope I didn't, I can't truly remember anymore). The nature of BioWare's hostile commentary in the forum back then literally sold me on the game. There was no way these guys would be so cavalier if any of what was said was truthful, but it turned out I was wrong about that. So I then realized it was defensiveness, and the company's posture has been defensiveness for a very long time now. I have a hard time trusting anything they say. They know what people want to hear, and that's why I'm amazed when they say something like "gamers have moved on from BG."
And again, I hope to enjoy the game. I actually am not opposed to the new direction for the series, even if it sounds like I am. I just want them to do new things within the context of this older format, versus trying to reinvent the wheel based on what the other guys are doing. I don't think a dialog wheel is as good as they do, for example, even if there's 9 of them and they're all within each other like Russian dolls. I just know that going in, I'm unlikely to play something that I would have thought could be a BioWare game 6 years ago. And I mean that as an ambiguous statement, because it has both positive and negative meanings.