Because there's absolutely no money to be made in China. There's no history or culture to explore in China. There's no opportunity in China except to bang Chinese chicks.
Statistically, most of them are losers in their own country, and they move China to become somebody. The only skills they have is their native languages which is in demand in China, and their foreign faces, which can be rented. Because they really represent the lower class of western people, they aren't helping China western relation.
Moving to china to enjoy its history and culture? please hippie.
If I'm guilty of judging someone based on the group he is belong to, at least I am quoting the correct statistics, unlike his.