Contagion and predation

The most reliable hand that the gender critical movement plays is the idea that transgender people are trying to usurp the role of biological women and even prey on them. It is the replacement theory. 

Transgender people are far from stupid and most highly educated in a topic that has been the elephant in the room often since earliest memory. They are aware of chromosomes, gametes, and the science related to them. 

But if criticals run with only the criticism that transgender people shouldn't be left alone to live their lives, it doesn't play well with the portion of the public that is most afraid and thus prone to hate. 

Moral panics work best when the public they are trying to scare fears for their own safety and sees potential consequences. Hence contagion and predation must be preached.