This reminds me of something I read of Thich Nhat Hanh's - don't answer the question, answer the questioner. The belief they're espousing is really secondary to the attitude that leads them to buy into it. I find your approach as not only more likely to effect positive change with that, it's just more compassionate and respectful.

There's an almost palpable element of dehumanisation among those ridiculing them and wanting to silence them, as if holding on to untruths makes them unworthy to exist in our society.