Actually, I saw that happen at a Detroit Tigers game in the 80s, when fans in center field began disrupting the game... the police stormed in and escorted them out of the stadium, the ones that resisted were arrested. So, as in this example, I support everyone's right to attend, just not disrupt the event.

So, using your example, you can buy the ticket to attend a sporting event, you have the right to enjoy the event and root for the other team, but you don't have the right to try to disrupt the event, people paid money to attend. In a visual event disruption means something different, than in an event where people are trying to listen to someone speak.

So, the issue is not whether or not you have a right to attend an event, or even protest, but at what point does your protest disrupt the event and violate the rights of others.

The issue comes down to "free speech". When is the intentional suppression of free speech including the use of speech to suppress speech unacceptable. I don't like censorship in any form including using shouting to suppress free speech.

If you want to hold a protest or rally, go for it. You should, invite everyone to hear your opinion, that is your right. But don't try to force them to listen to you or suppress their right to hear someone else's opinion.