The admins know the exact reason that you got banned and the report/reports filled against you. If they want, they will reply here with more info about what got you banned.

Users can get banned years after they posted something that was copy/pasted. So the fact that you wrote some posts, they remained visible for a long time, doesn't mean that you got banned for one of your most recent posts. In theory, it can be the first one you ever wrote. Admins usually react and assess reports sent by other forum members. If there is no report against you, no actions will be taken my admins most of the time.