I honestly can't believe anyone is giving you pushback on this. I've never been to an Army/Navy game, but have a handful of friends who served and have been to more than a handful of these games. Though not bringing up Trump/Biden specifically, they've said similar things that you have about how respectful the crowds are at these games. I've always assumed that whoever is Commander in Chief would be applauded at this games.
I'm not surprised Trump got applause at the game he attended as Commander In Chief. I wouldn't be surprised if Biden received a similar reception. The same would go for Kamala Harris. Given what you said about Clinton, Obama, Bush, etc, that would seem to check out.
Trying to say the cadets gave Trump the loudest ovation ever while Biden would probably get booed is dumb. But when you're in a cult I guess you have to toe the line.