Because the vinegar is perfect. It is exactly as vinegar should be, as it must be given the choices and events that led up to the moment of tasting. How else should it taste?
I don't believe that "perfect" is the equivalent of "ideal"... and that same distinction can be applied to the concept of "god", regardless of the dogmatic spin applied to it. God... the "first cause", the Initiator, the resonant essence of live across the multi-verse... IS perfect. So are each of us, for that matter. Any flaws we perceive are judgements we impose, evaluations based on very subjective societal, cultural, and experiential criteria. And hey... that's who we are... but the universe doesn't judge. The wind doesn't judge, a falling rock doesn't judge, a piece of steel pounded into a sword doesn't judge... it just is.
If you can remove your "self" from the equation and consider the possibility that everything IS perfect, then any perceived imperfections are flaws in our own awareness. And if that's true, then we can also work to neutralize the flaws and see the unverse, and each other, in a radically different light.
Now, I'm not such a purist as to suggest we all sit around and contemplate our navels and just "be"... all I'm suggesting is that if there is a saddness or anger or frustration in our lives, that it's US who can neutralize it, eliminate it, by removing judgement.

I'm just sharing these ideas, gang... this has been a great thread to read and each of you have stirred up some wonderful explorations for my own thoughts. Thanks for that and for letting me drop in my two-cents.