Perhaps you have just became cynical and lost your humanity overtime? BioWare makes it pretty clear what choices they'd want the player to choose. Synthesis is a perfect example of what BioWare believed was the "best" ending for ME3. Saving the quarians, making the geth independent, and curing the genophage all seem to be things BioWare wanted players to achieve.
Yes, because BioWare -never- thinks things through.
The Geth were predictable and never lied, because they didn't understand the concept. If the old Geth promised to stay in their territory and not interfer with the rest of the galaxy, then you could trust them. The new Geth are individuals now (however that worked, most unnecessary upgrade ever), so now they are unpredictable. They do not have the same needs as other species, which makes them superior in many ways. Over time, they'd overrun the entire galaxy... even if they initially didn't have any plans for that.
Synthesis ending makes no sense. If you already saved the Geth, reconciled them with the Quarians and got EDI to research ways to safely boink with Joker... then organic/synthetic co-existence has been proven already. We get along already. Why would you mess with the physical bodies of everyone in the galaxy? Why rape every living being with nonsense space magic? "Add your essence to the magic fountain and it will change everyone in the kingdom" ... bleh.
This only shows that BioWare has no idea about anything. The difference between synthetic and organic has never been the stuff they were made of, it was the way they think. I don't see how clogging up the synthetic hardware with unnecessary organic DNA would help the programs understand emotions and desires. That's like sneezing into your PC case and expecting a game to understand your feelings. Even worse... if the Geth are saved, then they have the Reaper upgrade and that means they are individuals with emotions already. EDI was one from the start. Synthesis wouldn't change -anything- for them.
Adding synthetic particles to organic cells isn't going to change anything either. We've had cyborgs before (Shepard as the most famous one) and it's not like people will behave any differently now that their eyes glow in the dark or that they can access the net directly in their brain.
Destroy ending has problems, too. Sure, you eradicate all synthetic life in the galaxy (awesome how the energy knows that it needs to fry a Geth program on server X but not touch the environmental control program running on server Y) but that leaves a power vacuum. Remember the leviathans? Those guys only stopped ruling the galaxy because the reapers hunted them down. Now that the reapers are gone and galactic civilization is weakened from the war and the destruction of much of their technology by red space magic... what exactly stops the rulers of old to rise from their slumber in the dark of the oceans and claim what used to be their realm? You basically trade an extinction cycle for eternal slavery.
Control is marginally better, as long as you can convince yourself that the AI copy of Shepard won't be a tyrant. You get to keep all the resources, all the knowledge and abilities of the Reapers. You control the galaxy, no one can stand against you. This allows the Geth to survive because now you can stop them if they spread too widely. The problem is: Power corrupts. How likely is it that AI Shep has safeguards to prevent them from exterminating the hanar because they are big, stupid jellyfish and Shep has had enough of their silliness? I still wonder why Shepard had to be disintegrated during the upload process. You'd think making a copy would work better if the original wasn't in agony and dying. What if that corrupted the datastream? Is AI Shep even a full copy or just a new theme run by the catalyst?
That leaves refusal, which is the best option. Rocks fall, everyone dies. Next cycle gets a headstart and wins. The only reason why this option wasn't popular is because we were too attached to "our" cycle and the people in it. Oh... and it required someone else to use the crucible, so basically we only postphoned the RGB decision by 50.000 years.
You will notice that none of these choices are about morality. They are about practicality. If you went by morals, then the most popular choices (Destroy and Synthesis) would be the worst ones. One requires you to sacrifice all synthetic life and quite a lot of your advanced technology, the other changes the physical bodies of everyone in the galaxy without their consent (which for some might be a fate worse than death). Refusal means throwing away everything you've done until then and leave it up to the next cycle. Control keeps the status quo and enforces peace... which might lead to stagnation but is otherwise the "best" choice if you went by morals.