Anyone who's made the mistake of taking the Stranraer ferry when there's an Old Firm match on knows just how true those words are.
Ok, I can see why people here support Man Utd, Liverpool etc. Our standard of football is awful, semi-pro stuff. That my dad (Stephen Hawking could probably have given him a hard time) used to play in the old B Division says it all.
Choosing to support either of the two Glasgow clubs is a whole different kettle of fish but I suppose the lines between religion and culture are especially blurry in this dysfunctional little statelet. I'm sure there are thousands of genuine Northern Irish Rangers and Celtic fans but, as you say, the mere wearing of one of their shirts is incitement to hatred in the wrong area from people who know nothing about football.
If anything, that level of shoutyness has, in my experience, become worse post ceasefire because the chances of someone actually pulling a gun on you have markedly decreased. I live in the shadow of a Catholic cathedral which is walked past by loads of young men from the biggest Protestant estate in the town on their way home from the pub at the weekend.
You'll regularly hear some winner start up singing The Sash to show how hard he is while staggering, full of Buckfast, past some empty bricks and mortar.