It is one thing to ask people should be able can use a bathroom, and another to ask questions about personal sexlife and behavior. i.e. if you asked people if you consider transwomen equally with women at birth as sexual partners, I bet the numbers fall through the floor.
Most heterosexual men identify as being attracted to women, and don't hold trans women in that category.
https://journals.sagepub.com/doi/abs/10.1177/026540751877913...
https://www.google.com/amp/s/www.psychologytoday.com/us/blog...
There are a lot of women I would not want to sleep with. Does not mean I question their gender.
You could ask whether there is a study to assert parent poster's assertion, too. All I could say is that the burden of proof seems to fall on you with your statement, but most would take parent's at face value.