IMO it's none of your business why someone is banned. The only people who have a right to know are the forum staff and the person who's banned. It's between us and them.
Most of the time, the reasons will be obvious, and even if they're not, the banning is in the past, and we shouldn't bring it up again and make a big deal out of it.
Finally, banning is fairly rare here.
What's that? My opinion is biased? Nahhhhhh...