Without proof to the contrary the assumption should be that the trans population has a similar proportion of rapists as any other does.
Since its been well established that essentially all rape no matter who is raping who goes under reported it is completely rational for women to be just as fearful as they would with any other stranger.
The question is whether bathroom bills forcing transpeople who wish to not break the law (potential rapists are obviously not part of this set...) into men's bathrooms, and a surrounding climate of generalised hostility towards anyone with any remotely masculine element of their physique or style in women's bathrooms actually meaningfully reduces the risk of rape, or just makes the environment more intimidating for everyone.
Cis women can perpetuate rape. Should we ban them from changing rooms too? How far through the looking glass does this have to go?!
It is a dessicated vegetative hominoid surely?