“The moon is not made of green cheese and anyone who says so is full of crap” is based on a statement regarding a fact that can be verified. Not even remotely the same as saying “Bill Smith is full of crap.”

If people want to piggyback on the name of someone who has 10x or 100x more followers than them, perhaps they should pick someone they admire and post something that IS within the terms here. Because public attacks are not. That’s the real difference here.