It really isn't transphobic to accept that transwomen are biologically, chemically & structurally male.
It's just a way of perceiving things.
When my brother looks at me, he sees a person. He knows my history, my sex and all that. But my sex is irrelevant to him - I happen to know this, because he likes to explain he "doesn't think of me as a woman." That's okay as it goes: our relationship's based on shared history, not physical sex.
When a man pinched my bum recently, it was because he sees me only as a woman. My personality and gender expression were of no interest to him. I wasn't performing femininity at the time; he merely observed my sex and conducted a gendered behaviour.
When the women in my support group talk to me, it's on the basis of my sex plus my personality.
... ...
It's similar when various people think of a transwoman.
Some will react only to her personality, with no interest in her sex or gender.
Some will react only to her physical sex or her perceived gender.
Some will respond to the entire balance of her sex and personality.
None of them are wrong. (Obviously the bum-pincher was wrong, it was just the most obtrusive example I had.)
My point is that you can't tell people how to think or feel. That way madness lies.
Just accept that people view things differently and try to understand.
Stop censoring other people. Stop enforcing unwanted labels on folk. Don't accept unwanted labels for yourself.