It's not actually changing the subject, it's merely an extension of your own logic. Your post as quoted here, is changing the subject as men of all 'races' already fight together.
No. It is changing the subject. Your logic makes no sense.
I changed the subject from size to race like he switched the subject from gender to size to show to that, for the same reason that separating black and white fighters would be racist, separating men and women fighters is sexist. Women are being treated differently based solely on the fact that they are women.