I think it's OK for you to be angry, but that your anger is misplaced.

Because, first, she is probably feeling the exact same way and is already pissed at herself for being that "stupid." Yeah, maybe it was a bad idea to ride home alone drunk, because society is just a shitty and dangerous place for women trying to get home at night.

This predator obviously knew she was completely drunk if she looked like she was falling asleep on the subway, and he probably said some compelling things that would make complete sense when you are drunk and exhausted and a pushy POS is asking you a bunch of questions/ pressuring you to do something.

But while you can be angry, (in the same way that you can be mad at family or friends for taking their own life), you have no right to take this out on her. Because despite emotions, the fact of the matter is some fucking awful predator saw an alone, drunk, girl on the subway and took advantage of her in so many ways - he disrespected her trust, body, and property.

And it might* have been avoided with a few steps - like not traveling alone at night, or taking a cab instead of the subway, but not always - cab drivers rape women too, and what about the sidewalk in front of her apartment? Shit happens - even when do we do everything that we're supposed to do. But when do we do everything right? Especially after drinking? We all do stupid shit, And sometimes, tragically, fucked up horrible people take advantage of that. :(

The only part about your post that makes me cringe is the questions, What did you expect? - because she expected to take the subway home after a night out and crash in her bed. That's it. I think it's presumptuous to say she invited him in. I've had guys follow me home - when I'm sober and it's hard enough to get rid of them - but when you're incapacitated? It's much harder. She might have said yeah, sure, there's the couch - but didn't think about it at all. And she might be emphasizing the "I invited him in" part just because she feels guilty.

Super sorry this happened. It's ridiculously scary when it does. Be angry, but don't take it out on her. And it sounds like you have all the practical stuff under control - you didn't mention it, but file a police report if you haven't already.

And in the future if this is something you really worry about, you can set up some precautions - and just explain that society is fucked up and predators exist, so you would feel better knowing she took a cab or went home with a friend or roommates, etc.