@Don Jefe - Unravel thy knickers, please.
Yes, yes, it's individuals that gather under banners and do 'orrible things to other individuals gathered under different (presumably less fancy) banners. Same old in-group/out-group gubbins and silly that's been going on since banners were first invented. And your point is?
Well, your point appears to be that some banners are in no way to blame for anything, and should be left alone. Not really how it works, though, is it? People, as you pointed out do gather under banners. It's human nature. I do, and so do you. I'm guessing you'd like to think you don't, but you do. You are showing every sign of doing so in what you're writing here. There's ostensibly nothing wrong with banners. I like heavy metal music, they like Justin Beiber. Oh, they're so silly. But no harm, no foul, I've got a bunch of people with whom it's really easy to start a conversation, and so do they. And we can all harmlessly roll our eyes at each other, all safe in the knowledge that the other group has it wrong. Yes, it's daft, but it appears to be an inescapable part of human nature; we will seek and find our in-group, and by definition be less cool and groovy to our out-group.
The problem isn't that we gather under banners per se; it's that some banners are overwhelmingly more problematic than others when it comes to the treatment of the out-group. You can write a big list of the banners which are really, really harmful. You'd have Nationalism on there, Race would probably have to make an appearance, as would Sexuality and possibly Football. But make no fucking mistake (ahem), Religion would be on there too.
The way civilisation copes with all these potentially harmful banners is to attempt to domesticate them, calm them down, blur the boundaries and have as many banners as possible so that an individual has numerous banners under which to gather, and thus numerous out-groups to scowl at. The more banners you're under, the more likely it is that someone in one of your out-groups is also in one of your in-groups. It's blurry, messy, confusing, and as a result people are less likely to stab each other in the face. Groovy.
Religion, to its (dis)credit has the extra-special sauce of offering extra-special in-group benefits even after death, and extra-nasty warrants against the out-group(s). It also has a history of fighting tooth and nail against letting its followers gather under too many banners. Religion, to put it bluntly, has not enjoyed the process of being civilised.
I'm not suggesting that religion is the biggest problem, but it is a problem. What individuals do is, I agree, their responsibility. But the idea that an individual doing something shitty like flying a plane into a building hasn't been dramatically influenced by religion is a little myopic. Is that individual still responsible? Yes. Should the religion also shoulder some responsibility? Most assuredly Yes. Were there a bunch of other reasons like economics and politics? Yes. Is it all sorts of complicated? Well, yeah.
You can call people short sighted idiots all you like. You can pretend that every man is an island, and you can keep glibly pointing to free will as if it were some magic shield warding off all influence. You can, hilariously enough, attempt to say that calling out the problems religion has caused is admitting that god is real. You can, apparently do this without seeing that ideas do matter, do have power, and can incite all sorts of shit without actually being correct.
You are free to do all of that. But, naturally enough, other people can look at what you've written and see it as obscurantism. I certainly did.
But hey, at least I didn't call you a fucking idiot, eh?