It is a simple measure, but it's also completely arbitrary. You are then making a judgement solely based on the fact that they are trans, not anything to do with actual advantage or fairness.

I'm not trying to be inflammatory or imply you're a bad person because of this, but that is a position based purely on transphobia. Unconscious transphobia maybe, but if you broke your motivations down for yourself honestly I think you'd see that that was really all there was behind your reasoning ultimately.