It’s not OK to target, discriminate or denigrate people because of ethnicity. Racism is wrong.
One’s belief system ..including religious beliefs .. are nothing to do with race. If you don’t like someone’s belief system then ..within the bounds of reason and respect ..it should be OK to say so. That has certainly been the approach on this site ..with the few exceptions where reason and respect have eluded the odd one or two. My own faith has been challenged many times on various threads..sometimes respectfully and at others with less reasonableness and respect. None of it was racism.