AFK in jail isn't punishment. It's, 'oh I just have to go get a drink and watch some tv for a bit.' Stop crying now that you actually have to spend some time working off your punishment. You could have been out half an hour ago, by the way. It's only 30 stools. But instead of doing your time, you run off to cry about it.
If you don't like it, stop breaking rules. That's the ENTIRE point of a jail system. Deterrent to rule breaking.