I'd say it's because the post is a very commonly used and reposted image in most meme and shitpost circles, it's not intended to cause harm and very obviously expresses as an absurdist-type post.
The difference between that, and telling someone to kill themselves in the comments is quite clear.
Look at it this way, we're not absolutely banning or deleting a particular order of words; We're banning harassment.
You can say a set of words on two occassions, it would be deleted in one and ignored in another. That's not an inconsistency with the rules or moderation system, it means that one of the occurrences of the set of words was clearly out of bad intent and meant to cause harm while one was funne.
Make sense?
Caption this Meme
