I do not agree with an instant ban for almost anything. An infraction/warning is usually enough to make the person stop talking about piracy and that is all that really matters, right? If they keep doing it, then banning them is a good idea because then you see that they are disregarding the rules on purpose.
Who knows, maybe that person will become a great contributing member to the forum one day. Banning them might discourage them from coming back to a site that, to them, seems hostile.