Having the right to do something is not the same as it being OK to do it.Is it OK to think it instead so?
Like if I see a fella dressed unconvincingly as a woman in town, is it alright if I think to myself "look at yer man there, the stupid cunt"?
Not that I'd ever do that of course.
I don't police your thoughts. You can think whatever you like about pronouns. I just think that courtesy and compassion costs nothing.