I wonder if the person you spoke of has taken the time to think through his stance - sounds as if they haven't.
I takes a minute to think through and especially if you are one who supports the entire LGBT-Q community.
I know it took time for me to think it all through and what I came up with is:
I support trans people fully. But some spaces - like sports, showers, and bathrooms were created to protect biological women’s privacy, safety, comfort based needs and the simple fact the biological male in sports, has advantage.
Inclusion matters, but so do boundaries. We can respect both.