Well, there are plenty of cults. So the concept of "religion being used for evil" shouldn't be alien to anybody. I think it is fair to say that some religious ideas are harmful (ie: getting together to drink cyanide, aka the Jim Jones cult / Peoples Temple)

And even for the Biblical literalists: they only have to look into the Bible to see the many examples of Pagan religions, from the Golden Calf, to Pharaoh / Exodus, and more, to understand that false gods exist. So surely, they should understand the importance of "getting religion correct".

So I think it is fair to call out certain religious doctrines to be "unhelpful", or even "evil", depending on the case. But I wouldn't generalize much further than that.