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.
What is this referring to Natural sugar or added sugar? Normally the yoghurt doesn't have added sugars beyond what were presswnt are in the milk originally.
For sauces you can easily read the labels and find which ones contain added sugar, at least in europ it's mandatory listing that.
It's added sugar - and yoplait/chobani add a lot of sugar. Yogurt with no added sugar has no more sugar than the milk used to make it does and it is mouth-puckeringly tangy. I make my own yogurt and you pretty much need honey with it to make it palatable with fruit (some people eat unsweetened yogurt without the honey... Those people scare me)
I de-sweetened my palate over time. I don't add any sweetener to my yogurt (made in an Instant Pot) . That said, I ferment it for 8 hours because I don't want it too tart. It's perfect for raita or tzaziki. For breakfast uses, I add cheap vanilla flavoring with fresh fruit. Not scary at all!