I think it’s because most of the people drinking “fine” wine today, and most of the people on this board, haven’t had much wine with additives. Because they haven’t had it, they think it is wrong.
As pointed out by a few others, there is a history of adding things to wine. Not wood chips, tannins, etc., that are supposed to mimic other flavors, but actual flavoring compounds that are supposed to be themselves.
In Uruguay they make wines like that - herb infused wines and I like that they’re not religious about it.
The notion of grapes as some unique expression of a piece of land is pretty recent after all. In the past people knew that some places produced better grapes than others, based only on the few grapes and varieties that they had in that specific region, but the grapes weren’t celebrated as expressing terroir or anything else. That’s all pretty modern. Those grapes were grown for wine. If your grapes got ripe enough each year to make a decent wine, you were happy and you liked that spot.
Most of the laws regarding what’s allowed to be grown in an area weren’t written because those particular grapes made better wine than anything else, they were written because the locals wanted to restrict things to what they had at the moment.
When did those rules start appearing? Rome once banned imports from Gaul to protect their own wine producers. More recently, in the mid 1700s the good folks in Bordeaux who owned the major trading houses banned wine from outside the region from being brought in. But producers continued to add as necessary - the wine just couldn’t be bulked in and sold off directly. The banning of Syrah only came about in the 1930s, mostly in response to the depression and WWII. Spain, France, Germany and Italy all modified or adopted rules in the 1970s that defined what the American market was to learn.
After those laws were passed and people in the US became familiar with those rules, we decided that’s how the world is supposed to be. Much later, as marketing, people started talking about the grapes as an expression of the land and vineyards because anyone can grow Cabernet Sauvignon. To make mine special I have to tell you about some stones or a large outcropping near the vineyard, or something else.
So to answer the question Chris posed - there’s absolutely nothing wrong with adding a bit of orange zest or rosemary or anything else to wine. It simply goes against what we’re accustomed to today and what we think is the correct order of the world.
As for grapes being special - so is everything. Onions from one farm, olives from another, apples from another and cherries from another. All are just as different as grapes when compared side by side. ALso cheese from one hillside in the spring vs the same in the fall vs the one on the other side of the hill. Most people don’t want to pay attention to those things so they are happy with industrial production, but many people are also happy with industrial production of wine, or else Yellow Tail and Meiomi wouldn’t sell so many bottles.