And she chooses to stay because?
Because *gasp* she wants to get laid? She likes being the center of attention? She likes meeting new people? She wants to practice her English? She wants to be entertained? She wants these 6 nubs to spend their money on drinks (assuming it wasn't free drinks)? She wants more orbiters in her daily life? She's trying to network with other people in a situation where she's got the higher social status to help her get ahead in her career? Maybe she's trying to get a gang bang? Reasons-a-plenty! And even then, why does she need a reason to want to stay?
All of these are regular, healthy human behaviors, I have no idea how you think otherwise.
On the other hand, do you think that a guy who talks to groups of women at parties are damaged as well?
Not sure how that squares with selling tips to marks with wallets as fat as their heads.
No PUA thinks of women as a good or commodity, even those that offer classes. The mere fact that you try and equate those two shows your ignorance on the subject.
Anyhow, that's enough derailing out of you.
Whilst some women certainly are looking for short term action, there are many places with better quality potential dates for them than international parties.
It depends on what you're into really. I've known several girls who have gone to live in other countries, come back and find that they don't quite fit into Japanese society anymore. I don't think that's bad on them really, especially with how closed the society is in general. Those types of women (hell, people in general), international thinkers, open mindedness, etc typically don't fit in that well into Japanese society and are going places where there are other like-minded people. A lot of these girls typically start at IP's for meeting people, then branching out from there.
I've met a lot of really amazing women at IP's, HUB, Roppongi bars, etc and I would never begrudge anyone for going to an IP if that's the kind of girl they're looking for. I would only begrudge someone who goes there because it's "easy for a quick lay" and isn't pushing themselves to get the kind of girls they really want.