Well, yes - the idea is to seek confirmation, from the user, before doing anything potentially damaging.
If you agree to it, or turn UAC off, you brought it on yourself, whatever it was. It's the operating system equivalent of "caution: may contain nuts" on half the items on the shelves in Tesco: easy for them to do, as a get-out in case anyone complains or threatens legal action.
Of course, you may ask why a user needs do anything potentially damaging in the first place, and that brings up the old conflict between "being secure" and "getting things done".
