Sure, our squad gets a TD or a sack and everyone jumps up and screams. Clearly, that is to be expected. But everyone making noise to make it more difficult for the opposing team is not about excitement. To deliberatively make noise (as opposed to the spontaneous screaming from excitement after a TD) it makes no difference whether one is sitting or standing.
Again, I'm tall, healthy and relatively young. I say this not for me but for those fans who have trouble standing for an entire game. It's not right to exclude them or make their experience miserable.
Sorry, I just disagree. I don't think that standing has a direct correlation/causation with louder noise, but what it does is create an environment where A) people see that others around them are visibly showing their excitement which doesn't make people nervous about being an outlier screaming, and B) people are more prone towards or willing to become excited. This isn't some weird tangential thought just cooked up by people around here - people get more excited when they're standing, which has side effects.
Reasonable people can disagree. No problem with that at all.
For me, I think it is a stretch to suggest that fans will be more nervous about screaming while sitting. Similarly suggesting that sitting makes one less prone to become excited when the team makes a good play also seems far fetched. The very fact that sometimes the phrase "jumping out of their seats" (or "brought them to their feet") is sometimes used would suggest exactly the opposite.
But like I said, reasonable people can disagree. But even if I agreed with you about the qualitative differences between sitting and standing, I wouldn't agree that the difference is worth disenfranchising a whole class of fans who simply cannot stand for that long. Many of those fans who physically can't stand for that long have done far more for the program in terms of dollars and support than any student jumping up and down on their seat ever will.