The reason you can appeal perm bans is the hope that overtime you will reconsider your actions and hopefully learn from them. I remember being on COD at 13 and saying some things that I would never say now at 18. Yes, you broke the rules, and yes morally what you did was very wrong; however, 4 years is a long time and the maturity level between a 13 y/o and 17 y/o are vastly different. If you've apologized directly to the person who you said these things about, then I think this is a fair, and well written appeal.
+1