I think the point is that when you see a story of obvious news value 100% ignored by major media, it adds credibility to the assumption that other events of possible terrorist-related activity which were eventually explained away could in fact have been similarly squelched.
This story will end with this guy being a depressed sick person who wanted to kill himself by blowing himself up, and who had a backpack with more explosives which he did not detonate which was later detonated by the police but subsequently un-occurred and did not happen.
I will add one thing - if this kid had gotten onto the field at halftime, gone to the center of the field with no one anywhere near, and killed himself (bomb or not), it WOULD be on the national news, and it would be obvious the motive was suicide since there was no one within say 30 years or whatever (hypothetical). The MSM likes dramatic public suicides, especially if they involve flyover country devices like guns and bombs. Guns are bad, bombs are bad, bomb instructions on the internet are bad, etc....
Instead there is an event much more suspicious in nature, with the obvoius question of terrorist intent, and the media say NOTHING.