Well, you asked, so I might as well give my opinion.
First, they are kids. They might not mean to become black out drunk. They might just not know how to drink. I once was told “If you can’t feel it when you gently bite your tongue stop drinking!” It sounded so silly that I never forgot it. I’ve never been black out drunk either. So there might be something to it.
But the other part circles back to this nasty slut shaming thing and a teenager’s under-developed logic. They keep hearing that when a woman is attacked, it’s her fault. That means she did something wrong. But since they are only doing what everyone else is doing, they are doing nothing wrong. And because they are doing nothing wrong, it won’t happen to them.