On any other forum I know, users don't get banned if they copy some text that can help someone else, and it's a pretty common thing to do since the beginning of the internet.
That may be so, but it isn't right. And on top of all that, people are usually earning money when they plagiarize someone's text, which makes it so much worse.
I'm not a big fan of Theymos's declaration that there will be some exceptions to the rule, but such is life. I think if he's going to allow successful appeals, they should be granted only for exceptional members who've contributed a lot to the community and only rarely. By rarely, I mean probably 3 cases per year. Rank shouldn't have anything to do with it, nor am I sad when a Legendary account gets busted for plagiarizing something. There are plenty of shitposting sig spammers who ranked up that much before the merit system.
Anyway, I don't think OP is the best candidate for a ban lift.