I'd say it's more nuanced than pure homophobia. It's a combination of homophobia, the fact that most T are heterosexual (so they call themselves gay and act like incels when real gay people don't want them), and the fact that they're Twitter lunatics who have just enough lucidity to realize that attacking, what is it, 96% of the population or whatever number of overwhelming majority it is, has the potential to end badly for their cause.