I agree, but what are those with less skilled but enthusiastic players to do? Are we to keep them out of team sports because we know they are going to be the weakest players on the team? No matter how much we practice with DS or how long he's played, he is not athletic and I am hard pressed to find a sport that he won't be the weakest player on the team. I am trying to guide him gently toward individual sports, because I fear the bullying he might be subjected to on team sports as he gets older. But, at the same time, I don't want to dampen his enthusiasm for something that he wants to do for fear of how he might be treated.
My heart goes out to the OP's DD. To me, it doesn't matter whether a child is a boy or a girl, or a skilled player or not, no one deserves to be treated the way her teammates are treating her.
What has worked for DS11 is that DH coaches or aids with his sport. DH coaches the spring soccer. It gave DS the ability to find the position that he is comfortable playing. Now he can go to other coaches and tell them were he will play best.
I too feel sorry for the OP DD. DS has been pick on on many team, even when he was playing on a team with friends. Parent coaching seems to be the only thing that really works.