Why does the fact that the person making a political statement knew that they were making a political statement make their banning okay?
For example, I have a first amendment right to stand on the street and cry out "that store over there has awful working conditions," and I'm not breaking any rules, but I'm well aware that the store may well not let me in anymore.
If the rules are ridiculous, then the reaction to them should be to dismantle the rules and disavow the rule-makers.