High glycemic index

Some argue that all carbohydrates can be problematic. If you like, you may read literature on low-carb high-fat keto diets.

All carbohydrates are problematic for people who are insulin resistant. Those with normal endocrine systems can tolerate limited quantities of carbohydrates with no negative effects, provided that overall energy balance is maintained.

Sugar is not precisely a carbohydrate. Sucrose is a disaccaride.

Sugar - here - covers more than just sucrose, especially when one of the more commonly used (and controversial) sweeteners is fructose, a monosaccharide.

Also, normal people (entirely correctly) call table sugar a carbohydrate. Why nerd snipe?

It’s not a nerd snipe. Some people or possibly all people digest monosaccharides and disaccharides differently.

Also, that might be a distinction without a difference in most cases, but sucrose and fructose also may not produce identical glycemic response to simple carbohydrates.

The point is this is a very complex topic, and some of it is at the edge of what humans know about nutrition.

It's precisely a carbohydrate.

https://startingstrength.com/article/sugar

Sugar as in sucrose is not strictly glucose, it's half fructose, which is basically poison/alcohol as far as your liver is concerned.