The destruction of the WTC and other attacks are known as “9/11”. Its not an official holiday and no one calls pearl harbor “12/7” day because its not catchy or resonant. If we call it independence day, that’s an american-dependent reference; people from other countries are not likely to know (or care) when our independence was declared or why that particular day was chosen to commemorate a 7 year long war or a 30+ year struggle, and are likely to have their own “Independence Day”, in some countries it might ironically mark independence from the rule of the US (like Phil).
It’s like Canada Day. I have no idea why July 1 is marked that way on my desk calendar, it just is. Canada never fought a war of independence and it was peacefully and gradually partitioned off from its parent nation and so unless I open the wikipedia article I have abs. no idea (nor do I care) why or what that is or how its celebrated.
Take Boxing Day. To an american, its WTH is that? But to a UK resident, they’re like–that’s when you open presents. And we say, you mean Christmas? And they say, well no–we don’t open presents Christmas morning thats a custom thats not universal. It might be better called “unboxing day” but there was a point not so long ago when regular people were too poor to afford to give gifts at regular intervals and so such a holiday might have been exceptional in the past but a common and universal event today. The timing of that “feast” or exchange is…entirely customary.
Or Guy Fawkes Day. They set off fireworks–that must be when the UK became independent? How does that relate to a catholic plot to blow up Parliament? Because…well…fireworks? Or perhaps we just liked your July 4th celebration idea and its alot like chinese new year but the chinese are able to provide fireworks all year round–can we just arbitrarily choose a certain holiday then decide how to celebrate it at some other point?
Same halloween. In the UK they didn’t have a dress-up holiday, but they liked that idea when they saw it in the US and so now they do.
Because these are all cultural customs and without culture-specific knowledge, they’re all meaningless.