Look at how sugar is primarily found in the natural world - its hidden in fruits and surrounded by fiber that our body has to also deal with.

Look at how sugar is found in the modern world - its in literally everything. Drinks, Yogurts, processed foods of all sorts. There is no fiber to help with the 'full' feeling. It is just sugar, which is high in caloric content.

Is sugar bad on its own? Of course not. Is it bad in the way modern society supplies it? I'd say so.