How do you define (for example) porn? Do you think you could come up with a definition of porn such that you could ban “porn” on the forum and no one would ever be upset or take issue with your definition?

The above is a hypothetical to get you to consider the larger point. There’s a reason why even the Supreme Court defined porn as “you know it when you see it”. Because you really can’t legislate this kind of shit in the manner you’re attempting to.

Obviously “porn posts” have never been a problem on these sites (beyond blatant malicious actors using them as an attack vector). The relavent issue here is “low effort/slop posts”. And yes, “you know it when you see it” / “it’s up to moderator discretion” is literally as good as it can get. There’s no magic words you can say which will set everything in perfect order.