I was football mad as a kid and obviously devoted to Barnsley, but that didn’t stop me ranking other clubs in order of preference. Man City over Utd, Everton over Liverpool, Spurs over Arsenal etc. My old firm team was and still is Rangers. I’m a committed atheist so no religious element involved at all. It’s just nice to have an interest in the outcome of the old firm games which are usually highly entertaining and I really don’t understand why it should be seen as any indicator of any sinister prejudice to express a preference.
Don't really have a Scottish team but if I did I would go for something based on the name like Caledonian Thistle or Queen of the South. Celtic and Rangers are boring names!
Mostly the main people in england jump on the rangers band wagon with like you say celtic been the catholic team with irish links. Rangers fans love england so much they came to Manchester in 2000s to play united and smashed the city center up, wednesday stopped doing the friendly with them because of all the bother and the charity collector getting mobbed. Scottish football is full of religion hibs/hearts rangers/celtic dundee/dundee United. Possibly the only thing that keeps the locals interested as the football is so poor.
Think they lost to St Petersburg if I remember correctly. They were throwing bottles at the big screen in Manchester centre when the opposition scored.