Western countries don't have the incentive to select for men to such a perilous degree. Chinese society is structured so that children take care of their parents in their old age, and men have more earning power to do so. Men have higher-earning careers over here, but the parent's aren't quite so dependent on that.

There's a very strong personal liberty counterargument, but then again overpopulation is dire and density itself also puts pressure on personal liberty.