Your statement would presuppose that atheists believe that Christianity is true.
Or that there is something about Christianity that makes their ideology always bump up against it. They don’t have to believe it for it to be a particularly painful thorn in the side of their world view. Take away any and all supernatural elements of Christian morality, and it still holds up as a pretty impressive system around which to build a civilization. The Left hates it for its success.
Their master Satan knows it’s true and he inspires them to attack it.