I do think moderation went one step too far regarding John.
Imo he was punished for being his own non harmfull overly expressive self, a warning should have been enough for what he did.
I don't remember the situation in question. But generally when it comes to bans, they're a result of a progressive system. If you let's say commit the exact same offense several times in a row, eventually you'll get a ban instead of a warning. And then a longer ban.
And if you haven't been in trouble for a long time, then we may be more lenient. Etc.
There's more to it, and there are exceptions, but basically we also look at a users mod history when deciding what to do.