Gay, lesbian, bi, or straight, people who are secure in their own gender identity and presentation all have a great deal of trouble being empathetic with folks in the transgender community. It can be hard for someone to understand how someone can question their own gender identity.
It can be even harder for people who are secure in their gender identity and are attracted only to those with the same identity to understand why anyone would question their gender identity, and want to alter their presentation and bodies to match a different identity than what they were assigned at birth.
The absolute worst treatment I've ever gotten in a retail establishment was from a person who identified, presented, and claimed to be attracted to male gender. I was looking for assistance in cosmetics, and he was the one the supervisor sent over to assist me. I got a constant stream of snark, and obviously bad advice. No, I do lot think blue glitter eyeshadow is a good daytime look for me.
He didn't know me, but from the snark, he didn't appear to care for transgender folks at all. That sort of thing doesn't reflect well on others in his own niche.
Being a member of one group in a sex-linked minority doesn't automatically make someone sympathetic to other minority factions. Jerkdom knows no bounds.