Let's leave the politics part out of the question - because OP is really asking about gifting etiquette. Let's say OP's kid and his friends were huge Nationals fans and they might be about to win the World Series and there are cute cupcakes with a Curly W.

Would they need to buy cupcakes for siblings? While that would be nice, I don't think it is necessary. The idea and gift are between OP's son and his friends.

If you can't afford the cupcakes for everyone, go with something cheaper. You may cause conflict in the household instead of celebration.