+1, common mistake. It's should've been brought up during your Cadet training. Anyways to answer your question here:
Basically when the order was issued all Jedi were deemed traitors to the Republic and were to be eliminated. I might not know why it's bannable still in OOC but rules are rules and they are to be followed. Anyways I believe you should be unbanned, it's a common mistake that happens when you get a trainer that isn't clear enough.