Opener:
When you log into the server for the first time, you are given a clear explanation to read the rules by simply typing /rules. There's a nice conga line of signs that follow to give you a brief low down on how things work around the server. If you are a new guest to a server, common sense would be to check out the rules first. You're even prompted twice, upon entry and via sign. So it's not that the resources weren't available, it's that they neglected to look into or adhere to the rules. Though it seems unfair at times, ignorance is not an excuse. When you grief, you are highly aware of what you are doing.
From what I've seen from the site, there seems to be an offense system. So if you were already warned, then you were banned justly for a repeated offense.
Opinion:
I do not agree that a rehabilitation class, or anything similar is necessary. Being the internet it's very easy to hide intentions, which makes this even more difficult. There's no way to tell if they're just following the ropes for re-entry so they can do it again once they are in the clear.
It was also mentioned that the point of the class was to 'teach them how it feels'. Unfortunately, people don't always learn/heal at the same pace (just like a real rehab), or merely don't want to change. I'm sure there would be a legitimate amount of those who are truly repentant, but unless constantly supervised there's no way to be sure. This is where the problem of the whole idea comes into play. Staff and moderators would have to spend their time playing Parole Officer with them, which eats up a lot of time and patience. It's not very fair that they would have to babysit specific people before letting them out of their sights again, especially with the numbers that are banned daily as aforementioned.
So, in my opinion, a rehab process would not be very efficient. But if the system were to implement something similar, I would think it would be something relative with the current process they have; IF they are willing to sacrifice the time (somewhat same problem as listed above).
There is a board where you can post an appeal for your ban. The impression I got from the page is that it's only to appeal a ban, in case you were unjustly banned by accident. This is very helpful, but does not quite fit what the OP was talking about. As I said earlier, no one changes over night, if at all. But, if the Staff and Moderators feel particularly lenient for the more minor offense bans, I would suggest allowing two appeals. The first appeal would be as the current available; if you felt like you were wrongly banned. The second appeal would only be allowed to be requested months later (let's say.. 3-4 months) for a 'second chance', accompanied with a letter of apology and steps you plan to make to show sincerity. However, if you mess up again after re-entry, permaban.
Conclusion:
Yes, people do deserve second chances, but there are plenty of measures already installed in the game (and renoted on the forum) about behavior and rules that are expected of us. If you are too lazy to read or follow them, then I think that whatever happens, happens for a reason. But if you truly feel that people deserve the time to be given a chance to change, then perhaps submit a modified version of your original post to the "Suggestions" section of the forums.
Edit: Also please don't be discouraged by my response, and keep in mind it is merely MY opinion, not everybody elses. So I wish you the best of luck.