Jeez mate, lighten up and let it go for christ sakes.
There's over 200,000 people go to LM, if you're getting upset about the behaviour of one moron, then you're a delicate flower indeed. Ok, it sounds like your yellow shirted spectator was a prize specimen, but so what, that's his problem, walk away and forget about it, he'll still be a moron tomorrow.
In any crowd that size you're going to get some idiots, it's statistically unavoidable, and we had some *rsehole dutch guys sitting behind us in the grandstand, but I see little point in bleating about it. Without digging out any photos I'll bet you weren't the only fans with British and German flags together, not by a long chalk. Are you seriously suggesting you're afraid of some sort of reprisal? My sympathies if you think this is actually likely, but to be honest it doesn't sound very feasible.
My best advice is to drink less coffee. Have you tried some of those herbal infusions?
H