Changes of meaning conveyed through capitalization are one thing in human-to-human communication, where the human brain is plenty capable of recognizing those instances given the context. They're quite another thing with computers, which have only extremely rudimentary capability for discerning context with a reliability that steadily decreases with the amount of direct human input. "Mission" and "mission" might mean different things, but then again, they might not. "Mission" in the middle of a sentence is obviously a proper noun, but "Mission" at the beginning of a sentence could be either, depending on the context. And even in the middle of a sentence it could possibly be an exception to the obvious interpretation, if, say, the writer were using capitalization for stylistic effect, as in "he was devoted to the Mission above all else, to the extent that I'm capitalizing it to show how important it was to him." How the hell is a computer suppose to figure that out?
And anyway, when it comes to filenames specifically, case-sensitivity is just retarded. As SomeGuy says, absolutely nobody does record organization (i.e. what a filesystem essentially is) with any regard to case, because it's never, ever important there. Of course, insisting on the Technically Correct implementation (see what I did there?) over the one that makes any sense in the actual use case is typical Unixoid behavior, so it's no surprise there.
Also, case-insensitivity in Microsoft operating systems has nothing whatsoever to do with thinking the users are stupid and everything to do with their deriving from OSes that didn't distinguish case (RT-11 by way of CP/M.)
