We don't. We give the same message to climate deniers, election outcome deniers, vaccine and mask deniers, insurrection deniers, flat earthers, and moon landing hoaxers.
And what do they all have in common? Belief by faith. The willingness to believe something without sufficient evidentiary support, often in the face of contradictory evidence. And organized, politicized religion is just as toxic as any of these.
This makes me an antitheist of sorts. I'm not against religion per se (most are just fine with me), just religions like Christianity and Islam that want to intrude into government and impose their values on unwilling people, or that teach that atheists (and homosexuals) are immoral and deserve to be scorned and treated with contempt.
I am in agreement with the OP. No atheist should accept that. All should actively denounce such religions until they shrink to the size that they are relevant only in the lives of willing believers.
Hitchens makes no bones about it. He also considers religion a net negative in the world (I'm pretty sure he means Christianity here, but possibly Islam as well, the two largest organized, politicized religions, both with angry gods that disapprove of almost everything - surely not the Druids or the Baha'i, for example):
- "We keep on being told that religion, whatever its imperfections, at least instills morality. On every side, there is conclusive evidence that the contrary is the case and that faith causes people to be more mean, more selfish, and perhaps above all, more stupid." - Christopher Hitchens
- "I am absolutely convinced that the main source of hatred in the world is religion. I think it should be treated with ridicule, hatred, and contempt, and I claim that right". - Christopher Hitchens