It's quite relevant at the moment considering our soldiers are still losing their lives in afghanistan - not wishing to simplify the global situation but the simple fact is they wouldn't be there if not for 9/11.
This tbh. That one event has affected our country considerably. Also I think part of the reason we carry on marking this day is that events like this don't happen very often in the US/UK, it came as a shock to everyone. It certainly came as a shock to me. Any loss of life is tragic, but if we were to commemerate every tragedy, we'd be doing it every single day.
I think in most cases, if something happens to America, it affects the rest of the world too.
Just as an aside, did the forum close for an hour on 7th July?