- That was the point of the original post you were answering to. If you were not addressing it, then you were not addressing the post.
- No, that is human mind for you. Emotions play a role in it, and the way we respond to visual stimuli is not entirely dictated by logic, as emotion can colour or even override logic, at times. However proportion matters; suspension of disbelief can only go so far. It is different to show a broken soldier being rescued by an unlikely but providential rescue team, and using green magic to make everyone and everything into cyborgs.
Actualy, imo, the endings pulled the suspension of disbelief beyond the breaking point at times, among other problems.
If you think Shepard survival is the most believable thing that happens in the last 5 hours, let’s agree to disagree.
Shepard die’s for the greater good? (that is another can of worms), but assuming she does, so you are saying that the visual scene where you see your choice to happen enhances the emotional impact of it? Ok.
Hope, as I have repeatedly pointed out, means there’s a chance of something to happen. Hope is a fragile thing, it needs some solid ground, or it can be broken.
Eh, if they had ended ME1 with the beginning scene of ME2, and said that this was the end of Shepard’s story, I would have a lot of problems seeing Shepard surviving. likewise, in ME3, after the repeated monumental beating she took, the bleeding, the ruined state of the station, the fact there is no one nearby, that the fleet is long gone, that Earth have their own problems, that… well, it needs a lot of headcanon to happen.
1. No, the original point was that there was so little to go on, people could only use logic and say Shepard died. The fact is, using logic isn't reliable. It had nothing to do with closure. More to do with how to make a logical conclusion, which doesn't help here.
2. Using broad generalizations is generally the wrong thing to do. Humans need visual stimuli for ever single situation like humans need french fries to go with every hamburger.
Shepard not burning up in atmosphere wasn't beyond belief, but Shepard doing it again is, this time, with them for the time being, alive and breathing? 
Shepard stopped being believable 2 1/2 years before ME3 even began.
Obviously the scene was for emotional effect. The scenes with the lost, the loved, dramatic music, panning in and out, that was obviously the point of it. Considering the Catalyst gave a zero percent chance of survival as the best case scenario, why would you expect anything more unless you metagamed. This was the end.
Shepard is alive when they shouldn't be. Nothing suggests that they are in any immediate danger. Everyone around is hopeful. It's as grounded as anything else.
The fact is, Shepard didn't survive before, and yet they were still able to come out of it alive. Mass Effect is the universe of many incredible feats becoming reality despite it making no logical sense. This time Shepard is definitely breathing, and to assume that they could not because of logic is faulty. Logic doesn't help you in Mass Effect so unless someone tells you no, believe whatever you want.