I don't really care if 100 seniors disagree with something that George Will wrote sometime in the past, and I don't really care if they'd prefer not to listen to him. I certainly would prefer not to listen to them. So, if they'd stayed away or walked out, I wouldn't really care about that either.
But I do care that they were rude, disrespectful, and misused the Baccalaureate service.
And still worse, it seems that none of their mentors (in the choir stalls; I'm looking at the photo published in PAW) saw fit to say anything. A simple "This is not OK, it's rude, please leave," would have sufficed.