Personal sniping in IMHO now?
Probably depends on where they are. There are places in the world where atheism or a very weak level of belief is the norm. There are other places where some specific religion is treated as a truth more true than science by the vast majority of authority figures that a person might meet. In the latter environment a certain level of critical thinking is required to cut through the bullshit.
Sure, but that doesn’t mean that critical thinking wasn’t involved. As the pillars of belief get chipped and knocked over one by one, the fervent certainty wanes as a consequence, until enough support has been lost that the brain glances around, shrugs, and discards belief.
Theists call this a crisis of faith. Early onset atheists call it “duh”.
In my experience all the rebellion took place while demonstrating my lack of belief. And really, since a person don’t consciously choose to believe or not (as you yourself just said), how could it possibly be the case that they choose to disbelieve just to spite somebody? You’re contradicting yourself.
While the whole “We’re not wrong, dammit!” reaction to oppression is definitely a factor, there really is a sense that other people out there believe in some really stupid, obviously false stuff. I mean, suppose you ran into somebody who was wearing a shirt, who announced, “I am not wearing a shirt!”, persisting in these claims regardless of the manifest evidence to the contrary. Once you’d eliminated the possibility that they were faking it to mess with you, one natural reaction would be to think that that person was an idiot, right? That’s what a lot of religions look like from the outside. It actually took me a while to figure out that believing in idiotic things didn’t mean the person was totally an idiot - compartmentalization is totally a thing and an idiotic notion can get lodged firmly in the idea of anyone, no mater how smart they are. (Presumably even me!)
So yeah, there was definitely a time when I thought that religious people were all idiots, what with them periodically and regularly talking and acting like idiots. It was a cause of some consternation, how an otherwise smart person could be so dumb, until I got a little older and figured it out.