I’ve seen this picture on Twitter/X at a different angle. The guy and those around him were looking up at the Jumbotron, because they had Trump on it. So he was giving the finger to Trump, not DeSantis. In fact, I saw pictures from the game of multiple people looking up at Trump beneath his glass window, giving him the finger. When he appeared on the Jumbotron, he was loudly booed by half of the people in the Iowa stadium.