@SoMuchForSummerLove
Why would it be hard though? There are kids from Poland, Russia, England, Hungary, etc etc, in my kids classes - I'm sure they're already pretty clear that they live in Scotland. They don't get the vapours on St Andrews Day or Burns Night.
That's not quite the same, though. St Andrews day etc is a celebration of Scottish culture/ Scottishness etc. Which, as that's the country you live in, is fine. No competition or xenophobia or anything. Just saying "Scotland is great". Which we can all get on board with.
Football, though, is the vast majority of people in a room absolutely willing the country where you/ your parents were born, that you may well have a lot of love for and affinity with, to lose the game. And expressing that desire for 90 minutes, with varying degrees of volume and cheers/ groans. It won't be violent or nasty in a classroom, obviously, but I can imagine that feels pretty uncomfortable - especially as a child, with friends closing ranks against you and supporting the other team (potentially, of course. I'm assuming in an actual situation like that the children would show some sympathy and some would also "support" their classmate's team, even if they wouldn't naturally, because children are generally nice like that).
It's not like an actual team game where half the class win and half lose, so you can share your joy or frustration with the others. Having 26/27ths of a class wanting one outcome could well feel a bit hard for the 1/27th - especially if the outcome is totally out of their control. If you win, you wouldn't be able to celebrate because your classmates would be upset, and if you lose you'd have to deal with celebration from the others, which may be seen as gloaty with sufficient numbers/ characters... But, hey, that's life. Never too early for children to learn important life lessons that it's difficult having a different opinion or being set apart in some way from the majority, and that sometimes we have to do things that we don't like doing because other people like doing it.
I'm glad England/ Scotland is after the school day. Though I imagine that would at least be a bit more evenly matched in DSs class.