I don't watch American football

I hold quite a bit of dislike for the sport as a concept, and even more so, its execution, but I do have one burning question. Why do the commentators shout like that when announcing things? Like ok. The man is running, check. The man is carrying a ball, check. Nothing noteworthy is occurring, check. But then theres some 50 year old man in the background of the TV absolutely SCREAMING at the top of his lungs sounding like he's half a decibel away from blowing out his vocal cords. It cannot be healthy, it's very grating, it's actually kind of alarming. I just assume it adds some sort of an element of entertainment for the average viewer? It's just, to me, like "why are we yelling?"