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.
A cup of pure tomato paste has 32g of sugar, since tomatoes are fruits that contain sugar. It doesn't look like that sauce has any added sugar at all based on the ingredients, but it does have carrots, which are also high in sugar (for a vegetable)