Whose enemy?
But good words!
Of course they can believe anything they want - what I'm talking about is behavior, including speech. The behavior I'd like see the thinking world think is, well, silly if not intolerable, is the behavior of acting as if any god were actually real, that any supernatural force exist in the natural world, that natural powers can be effectively petitioned, that you survive your death, and so on.
Note that racism and sexism are bad examples of this kind of wish-it-were-intolerable behavior. A better example would be a grownup who insists on the actual reality of leprechauns, or goblins, or any such silliness. It's just silly for a grown person to still believe in fairy tales.
And the parallels with racism and sexism and other intolerables appear when faith is applied - that is, when the differences in fairy tales translate into kill the people who believe in different fairy tales, or don't hire the person if they don't at least believe in some fairy tale, or into the Kansas and Dover PA debacles of whether science can actually be taught in a science class! The damage is intolerable! It should be, at least, OK, I'm climbing back down off my high soapbox.