Parole doesn't work on the internet.

Or at least in the cases where people are banned indefinitely specifically in the South Pacific.

In real life, where a "ban" means prison, people who get parole actually know how it feels to be in prison and would never want to go back.

But in TSP, that's not the same. An indefinite ban isn't a punishment, its just a deportation, and on the internet where thousands of other communities exist, many times people will just hop over to them. If they ever return, more likely than not they'll be using the parole system as a chance to try again their malicious intents. Not to mention the anonymous nature of the internet (for reference see the Greater Internet F***wad Theory)

While they'll always be people who respect their second chance, those people don't come around often enough to make a parole system worth it.