I don't think anybody believes that trans people are fully biologically changed to the other sex, that's not even in question. The debate is really about rights and nothing more. The sports question will be decided by those governing bodies.
I competed in a number of sports, team and individual. If I had been told I was expected to face a biologically male opponent in a judo competition, I'd have quit in protest rather than participate in a farce like that.
-k