Banned from Reddit alltogether, banned from a subreddit, or banned by Reddit because you were previously banned on this subreddit and were ban evading?

There are so many possible reasons for being banned in a subreddit.

Mods on Reddit are pretty free to do what they want. There are guidelines by Reddit but they are nothing more than suggestions and unless the mods of a subreddit are racists, they won't do anything. Sometimes not even then look how long it took for /r/TheDonald to being banned.