Earlier quoted context omitted.
Your argument is, "Don't say 'I believe X and if you disagree with me you're bad'. Just say, 'I believe X.'" But then literally in the same sentence , you say, "If you do the thing I don't like (in this case, calling people bigots because they don't support lgbtq) *then you are self-aggrandizing." "Nobody should be called a bigot for their views on lgbtq, but it's virtuous to call people self-aggrandizing for calling…
You can argue hypocrisy or about the way the argument is presented here, but it’s beside the point. Saying “there is only one correct opinion on this matter and if you disagree then you’re a bigot” is exactly what is driving people to oppose those opinions, regardless of whether they are correct. It’s just a really, really poor move, in terms of rhetorical strategy.
Calling individuals may even further radicalize them, as you say. I am not convinced on this point, I sort of think their mind is not changing either way, but maybe I am wrong.
What I am sure of is, it is not the responsibility of people whose rights are being taken away to be polite to their oppressors for the sake of rhetorical strategy.