That's not true, there's a few newer songs, the one that gets sung most often nowadays is Every Saturday We Follow, then 4 Lads Had A Dream, then older stuff life the Blue Sea of Ibrox, & the player songs about Morelos & Kent & the like, so that's just not true.
Listen, I dont want to get involved in whataboutery, but there's a few of those places you listed such as Sunderland, Manchester etc as well as Amsterdam, Stockholm & the like that trouble seem to have found you guys so yeah, your hardly innocent that you like to make out. There's hatred & interlorence from both sides, there's no point in trying to deny otherwise. That's the thing with rivalry, it's always a 2 way street, you can't claim 1 set is driven by pure hatred & the other side are sweetness & light & their farts smell of roses, no sane person would believe that to be true I'm afraid. When their is such rivalry even though you don't like to admit it it's because it mirrors the other side I'm afraid, & that's just a fact of life.