I'll admit that our fanbase has it's fair share of idiots. Celtic have generally stamped out "sectarianism" within their support though. I'm sure there are a few exceptions, but you'll rarely hear sectarian comments at Celtic Park these days. There's still a problem with political songs, particularly among the away support. I don't think songs about the IRA belong in football, despite the fact that the majority of them are celebrating the original Irish Republican Army and their actions during the Irish War of independence. I don't like those songs being sung at a football match, but I don't have a huge problem with them. A lot of people compare them with "Flower of Scotland". So i can see the point. I still tend to avoid joining in with them though.
There have been a few occasions where there have been people singing about the PIRA recently though. Which is just embarrassing and I know a lot of people aren't happy about it within our support. Especially when we play Hearts. Everything seems to descend into chaos every time we visit Tynecastle.