Alex was citing rule 5, "No racial obscenities, hate speech, or politics." Confederate flags are a very political matter and obviously considerate hate speech to a great many people. Further, having already been warned less than an hour before about using such language on our server it should have been clear that this sort of behavior is not tolerated on our server.
Your ban is only temporary and is effectively a strong warning. Your ban will remain in effect as several messaged warnings didn't deter you.
From our chat logs I see that our rule didn't make sense to you. If you are still in need of an explanation for these rules, let me know and I can provide one.