Calm down man.
Yes but the distance traveled by a mouse on a mousepad vs a tiny joystick on a controller is completely different. They literally use this as a measure to set your in-game sensitivity - cm travelled on your mousepad to make 360. So you can play with low sensitivity but still have great whip reactions because you have a large area to move on your mousepad. They turn their senstivity up to match your ability to whip, but they still have to deal with the tiny physical travel of the joystick and even then they lose short-area preciseness because they've turned their sensitivity up. Or if they turn their sensitivity down, then they have the short-area preciseness but now they look like they're moving through quicksand when they try to turn. They're at a physical disadvantage with the tiny joystick, and aim-assist is trying to correct that and level the playing field by letting them play with higher sensitivity (so they can whip turn like you) but then auto-lowering their sensitivity when they get on target (so they can have short-area preciseness, like you). Aim-assist is trying to emulate what it's like to use a mouse but doing so with a tiny joystick.
Gonna have to ask for a shred of evidence before you can make a sweeping generalization like that.
Yes, FPS does matter. Refreshing at 144fps or higher results in a PC getting a several ms advantage over someone playing at 60fps. If everyone has an identical reaction time, getting to react ever so slightly sooner is a very slight advantage. Consoles have hardware limitations. This is admittedly not a large advantage, but it does exist so you can't say it has NOTHING to do with it.
This is...not how it works. Even if you had AI play each other so all the skill levels were identical, you still have situational advantages between players in various encounters. This is one of the biggest skills in a BR game - situational awareness, planning, gamesense etc - you can have over opponents of similar physical skills. Better elevation, better cover, sticking together, trading with teammates, etc. None of that has to do with gunskill.
So no, console players do not automatically lose against PC players just because a mouse is easier to aim with. There are other ways to gain advantages over players if you're smart. And no, console players don't quit every time they see a PC player, because they don't die 100% of the time against PC players. The same way you, despite going on and on about how aim-assist is overpowered, you don't die to console players 100% of the time and you don't quit lobbies when you see them. Because...wait for it....you do kill console players a lot of the time. You just don't think anything about those - that's just you being "good". You only complain when they kill you, and the crutch you reach for is "aim-assist", just like players blame lag and hacking. Players are always wanting to blame something when they die - they are the only ones who can make good plays, any enemies who make good plays are either lucky, hacking, or it was lag. Or now..."it was aim-assist". "If they don't have aim-assist I obvoiusly would've killed that n00b."
Just stop man. Aim-assist is leveling the playing field. There is no advantage over a PC player - any PC player choosing to use a controller is only hurting himself in the long run. It might make him better at staying on target, but he will forever be worse at whip-sniping and quick-scoping, things that actually require quick aiming which is 10x easier with a mouse instead of a tiny joystick.