As long as they are going there anyway, why don't they meet a nice Chinese man?
Because married Chinese men are only allowed to give birth to one child and most choose to raise male babies; deposing of any female babies they birth.
What I don't understand about the views of people who see these women as selfish is: how is a married couple having a child any less selfish?
I think a single woman who chooses to adopt is essentially the opposite: instead of conceiving a child for her own selfish purposes, she chooses to mother a child that is not wanted to begin with.
The attitudes towards these single woman isn't really much worse than the attitudes towards girls in China if you ask me.