Wow, he really doesn't get it. "Wow, you're so pretty, I wish I was as pretty as you!" should not be met with, "Yeah, you're right, I'm hot." Come on, dude. This comment is dead-on, women like to reassure one another and "open up" about their flaws because nobody wants to be around someone who thinks they're better than the rest.
There's even a Mean Girls scene about it.
Now, maybe in an ideal world, there'd be no need to criticize yourself before you can compliment others. But that's separate from the fact that if someone is being down on themselves, it's polite to say something nice back!