I agree with the OP. I sincerely doubt he is as big a jerk as some want to portray him as. Sure he has made some badly worded posts. It's clear, at least to me, that his gf is ust very naive. Nothing wrong with being naive. Sure, something could have happened her, just like something could have happened him if he let a stranger in to his apartment. Nothing gender specific here either, right?
I think his reaction was appropriate. In any naive situation, you sometimes need to pop that balloon because otherwise they will just say "Yeah, yeah, I get it". A stern talking to, explaining why he feels it was a bad decision to let strangers in, is fine by me. As a kid, if I picked up a knife by the blade, my parents would sternly tell me whaat I was doing was unsafe. But... I didn't get cut... True, but that's not the point they were making. Sure it seemed like they were mad at me for doing it at all... but were they? No. They were just trying to make sure I realised how my safety was important to them and that in the future, I shouldn't pick up the knife the wrong way.
This isn't a gender specific issue and to paint the OP as some kind of controlling, abusive bf is pretty shitty form.
edit: GOD DAMN MY SLOW TYPING SKILLZ!!!