Men’s college basketball stats list the weights of men, but they don’t do this for women. Are women athletes so uptight about this number that they don’t want it displayed?
Interesting question. I knew there would be one sport where they couldn’t get away with it. 
Interestingly, all the women’s wrestling links have the weights in k.
I think it’s silly myself. Is a woman going to tell someone her weight and then that person walks off thinking “Jesus, never saw that one coming!”. You don’t need a number to have an observation of a person’s weight!
All that aside, I thing your WAG is probably correct.
I’m sure it dates to a time when it was just unthinkable, and it has just never been changed.