Oh my god is that ever stupid. I have heard men make "all women are alike" type assumptions before, but this one takes the cake. Hating the idea of a world without your gender is one thing... this is quite another.About women autoreproducing... well if a thing like an all-women world should ever happen, my guess is that it would fall to a quick end, as the basical needed variety for the race would be missing.
Anyway, as to Imoen... I think it's impossible to decide, really. I get the same feeling about her that JC gets. She could like girls, though.
I wouldn't say that open-mindedness or emotion would make her bi, on the other hand... I personally am very open-minded. I think many women are beautiful, and on an emotional/spiritual level, find them to be great--some I could almost have imagined sharing a life with. But at the same time, there's a spark missing... there's no romantic attraction, and there's no desire for sex. So although Imoen does seem open to me, that's not to say she likes both genders at all. She might be like me--sometimes having wished she were bi because she knows some great women, but unable to muster any passion for them even if she tries. Same if she's lesbian--maybe she knows some great men, but can't like them THAT way.