Well, actually the point is that using bad wine for cooking is I guess OK, but if I wouldn't drink it I also won't cook with it. The real issue is that an open bottle of wine to cook with is gonna be crap in about a week and should be thrown out. Vinegar, however, is another possibility of what you can do with leftover wine.

Scenario: you have a container of vinegar in the process. It requires no effort, just a place to put the jar or crock with a piece of cloth over the top to keep the bugs out.

You have a partial bottle of leftover wine that you have been using in the kitchen to cook with for a few days, maybe a week. You can now pour the remains in the vinegar crock instead of throwing it out.

You open a bottle of wine that turns out to be plonk. It is not corked( effected with a contaminated cork that makes it taste like wet cardboard) it is just a mediocre or poor wine or just something that doesn't suit your fancy, you can pour it in the crock also.

Leftover wine after a party that normally gets poured down the drain, in the crock instead.

Supposedly you can make a better red wine vinegar at home than most of what you purchase.

Mind you, I am brand new at this and very possibly this will turn out to be an idea that looks good on paper but is not too practical. I agree, Martin, that trying to make wine is beyond my scope. I will have to let you know how it progresses.