Well "F... the Mormons" isn't very original. When I grew up (back in the 1980's) something like that would have been rather mild. Insulting chants against the other team was integral part of the sport, and we spent lots of time coming up with truly cruel ones. In fact, the principal at one of our rival schools got arrested for diddling boys, made all the local news channels. Well, the very next game we had a rather nasty chant about "Dwayne (the principals name) making all that teams tight ends into wide receivers."
Yeah, we went there, and the funny thing is nobody cared, in fact we actually had parents laughing and joining in.