I was explaining this to my daughter in quite simplified terms the other day- we evolved to taste sugar and enjoy it because finding a sweet edible plant meant we had a source of energy to help us hunt that day. Pretty useful if you’re a hunter-gatherer.
So we seek out sugar. Now we can get it whenever we want it, in much more massive quantities than we are supposed to be processing. Most of us are addicted. I’m not an exception.
Nah, a small amount of sugar improves tomato sauce. It cuts the acidity.
After reading the other comments for a bit, it may depend on the tomatoes. The tomatoes I tend to use don’t need to balance out as much, I suppose