At my high school (been out 7 years) they could put absolutely anything they wanted, within reason. Didn't have to illustrate any points or discussion.
I remember one of my 5th grade teachers was a huge Vandy fan who had a blown up picture of two players tackling each other on the wall. The narration at the bottom was something about Vandy beating UT. I can't remember the year, but FWIW, the picture was in black and white. She didn't make any guesses as to which team she rooted for.
It's trash talking a rival. I don't have to bring myself down to their level. I make it a point to trash talk a candy fan any chance I get. If your looking for a reason to feel sorry for them, that's on you. You handle things your way, and I will do it my way. To HELL with candy!