Mom leaves a hundred dollar bill on the desk and her kid spends it.

Someone leaves a hundred dollar bill on the desk and his mate spends it for lolz.

Are these significantly different (if no less unjust)?

Sorry, no.

"Just do more of this, but broaden the categories to include posting…" and here you are already thrusting yourself down the slippery slope. You went from "gore, rape, and torture", all of which inherently not easy to prove in and of themselves, but in just a matter of minutes you've already "broadened the categories" to "visually horrifying" (based on who's opinion?) and which is "known to cause PTSD" (known and determined by whom? Not even to mention that PTSD is a professional construct), but also including having to know where people do and do not expect to see something that is something based on the above mentioned ambiguous determinations.

It did not take you long at all to just vault yourself down the full on dictator slope. Next up, let me guess, you want to prevent people's access to the internet if they say things you don't agree with because "word are violence" and then "micro-aggressions are violence", simply because you have the control to abuse. Unfortunately that is already the situation right now, but it does not need to be made worse, because it will only thrust us all down a path of overplaying the unrelenting abuse that I can assure you people will not like the inevitable consequences of one bit.

Let me also remind you that the US has the supreme law of the land that supersedes all other laws, the First Amendment to the Constitution that states that no law may abridge the freedom of speech, regardless of whether you like it or not.