“If girls are competitive in the lower weight classes but not in the higher ones, so what.”
The “so what” is that, for adult males, their muscles are pound for pound stronger than those of a woman. That doesn’t mean they could never beat a guy wrestling, but it says to me that, as muscle mass becomes a bigger factor (say, after puberty, and as you go up in weigh classes), the chances of women being competitive are going to get real slim.
I think it’s an entirely different situation than just trying to slim down to get into the lower weight class. The guys are trying to maximize their potential, whatever their size, while women wrestling with men are just going to have to hope they are small enough to stay in the weight classes where they have a chance, otherwise they are out of luck.