First- you walk the fine line between our rules as often as you can.
Second- maybe you deserved a better warning.
But would you have actually listened? probably not. More likely you would have started an argument about it not explicitly being against the rules.
Third- youre lucky he decided to pardon you upon appeal. I would of left you banned for at least 3 days if id caught you doing something so stupid after being here so long.
"it's just otaku expressing his disapproval of my joke"- its not "just" anybody: its a staff member telling you that your joke isnt approved. understand it next time.