First off, I'm not a winemaker other than a bit of homemade stuff. Actually, if I was a winemaker, I wouldn't be telling you many of the things done to your wine. Second, nothing mentioned here will hurt you. Everything done in the cellar is to make the wine better, or sometimes to save time or money, in the opinion of the people making the wine. Sometimes it's for taste, sometimes for looks. The U.S. gov't, the TTB, controls what can legally be added.
There are two groupings of wine manipulations, things added and processes done to the juice or wine.

