Because, for the general populace, there are few and far things to me that are more patriotic that exercising your constitutional rights. Obviously serving your country, in some capacity, brings a level of patriotism that far exceeds that, but back to the general populace which Kaep is part of...
That US Constitution, which Kaep's utilizing the rights bestowed upon him by, is far more important than the flag that he's supposedly disrespecting. And using those constitutional rights, in an effort to make this country a better place, to me, is patriotism personified