Do people who disagree deserve to be called ‘transphobic’?
No.
‘Phobic’ behaviour has a definition. It’s the same as discrimination against someone for anybprotected characteristic.
If I fire Sarah because she is Christian, or abuse her for her religion in the street, or deny her her freedom of worship I am a. An asshole and b. Breaking the law.
If I discuss my dislike of/disagreement of the tenets of Christianity in public or in private in a setting that does not directly disadvantage Sarah then I am neither breakingvthe law nor behaving imorally.
It is VITAL to be able to discuss, and question, and yes, mock and ridicule an ideology. no ideology has the protection of law (thank fuck, despite Blair trying to get blasphemy laws on the books...)
Would I discriminate against, mock or disadvantage a trans individual? Absolutely not. They have rights and deserve to participate in society without fear.
Will I assert my right to pick apart the TRA ideology? Goddamn right I will. I think it’s deeply damaging to the safety of women and girls.
Ideology is not and can never be protected in a free society. Every single society that does protect ideologies is a basket case.