I'm not confused as to how it's legal. I'm quite sure it's not. However, it seems to me that except in rare cases, no matter the color of the tie worn by the politician, nominal legality is not an impediment. There's an ideological opponent out there who must be publicly punished for his wrongness as an example to anyone else who might dare be wrong, and while the Constitution forbids various explicit means of doing so, there are myriad implicit ways of approaching the same goal.