Being made fun of for anything that people biologically cannot change is hate speech. It’s not some complicated quagmire of laws you are trying to make it out to be.
So what is hate speech in a way that can be automated?
Will that automated approach squelch valuable speech too? What if a certain disease impacts an ethnicity more than others? Is ‘black people tend to Sickle Cell more often than white people’ hate speech? Could a moderator decide that, given the fines? Could automation?
This is where a very loud problem is and this is the complexity you’re claiming is ‘simple’.
If you read it carefully, I just “made fun of” people who are unimaginative. Is that an innate trait? Should my content be censored?
Should a comment on a video of a tall person that says “how’s the weather up there?” be censored using criminal liability?
This criminalizes even hosting the discussion about what beliefs along these lines are or are not correct. Someone posts about their (mistaken) beliefs, in essence asking about a disproven theory correlating race and IQ. Other people correct them, educating them as well as any other lurkers. Should the sysadmins go to jail for not deleting the entire thread?
Being wrong on the internet should not be illegal.
There is absolutely not a bright line, and it is somewhat naive or perhaps even dishonest to claim otherwise.
Given that reddit is banning the word "retard"... the answer may soon be "yes, it should".