What exactly is he protecting them from? I would guess that frequency of a rapist that also crossdresses is like maybe one in a million? And if we are talking about a transgendered person or someone that is transitioning, they probably don't have the ability to assault someone if they wanted to. The vast majority of all people transitioning from m2f are trying to be as invisible as possible, not trying to infiltrate the women's restroom for nefarious reasons.
This is all about ignorance. Only education can solve these deeply disturbing internal prejudices that people are projecting onto the trans-community, and only a lawsuit forces them to review their own BS.
What is really ironic, is that if this guy met some gal that was cute and funny & didn't know she had transitioned, he would probably try to take her home. He is a pig.