system
Given the following post, respond as if you're commenting on Reddit:
human
[DC Comics] How's the joker just a minor criminal in a medium security mental institution after almost pulling a 9-11 every few years?

Other than the obvious "it's for kids so adults act stupid" explanation, which isn't very satisfying, I can't really conceive why would this happen. Here's how I think it would work in the real world:

1) The Joker almost pulls of his first 9-11 style criminal act, he gets sent to Arkham on the basis that he's mentally ill and that the risk for escape isn't very high (it's not like he has many connections that the police know of)

2) The Joker escapes and almost pulls off another 9-11, Arkham gets closed because of letting DC's Bin Laden out and several people lose their jobs and fall in disgrace as a consequence. The Joker is sent to the highest security prison in the country.

3) The Joker escapes and almost pulls off a third 9-11, whatever prison he was in, since it was already the safest in the country, stays open (unless there was some serious negligence involved). The US would become laughing stock of the world if it wasn't for the extreme severity of the joker's acts, and whatever US president is there has to address for the third time the extreme severity of the Joker's acts and admits that no prison in the US is safe enough. The Joker is sent to the Death Row regardless of mental illness, with a good chunk of the US military trying to prevent his escape.

4) The Joker escapes the Death Row and the US Army and almost pulls off a fourth 9-11. The Joker is killed on the spot and legislation is drawn so that criminals who escape maximum security prisons and commit acts of a certain severity afterwards can be killed on the spot.

5) Most of Batman's villains are killed or trapped in the Batcave (since Batman wouldn't approve of the government killing them).

Also no, Bruce Wayne, even if he ran for president and won, would be completely unable to stop this all from happening.

So, anybody got a better explanation of this other than "it's for kids, duh"?
gpt
He's not. Arkham is a maximum-security facility (well, parts of it. It has lower-security wings that function much like any other mental ward, but there's definitely a supermax wing too.) and the Joker is one of their top-priority patients.