Take Perdue and the points
I disagree. If this were a military ceremony, or official federal government event, or any event with a military honor guard present, then it would be appropriate to expect all in attendance to stand for the National Anthem.
However, it was an intercollegiate basketball game. It's inappropriate to include pretentious displays of patriotism. And it is perfectly legal for anyone present to decline to stand for the Anthem if it's performed.
Resist the MAGA pressure to move closer to authoritarianism. Let's just enjoy the ballgame, shall we?