I like natural cane sugar, I admit I consume more than I should; but I actively avoid substitutes since history has shown they are never better for you and every one eventually proves worse than the natural sugar it replaces.
Not to blindly defend erthyritol, we should definitely look at it closer. But "less bad" doesn't mean good. Sugar is still very unhealthy.
As far as history: let me give you an extremely quick rundown. Diabetes was known to the ancients, but was extremely rare until the 18th century, when British sugar plantations made it affordable. (The slave labor involved wasn't very healthy, either). That's when diabetes, obesity, and extreme amounts of tooth decay reached the British working class.
Sugar was a very popular trading commodity for native populations. And they were even less equipped to deal with it: tooth loss, diabetes, obesity and cancer skyrocketed in these populations soon after Western diets were introduced (British Empire medical records are a great source for this).
Maybe we are back to that 'over processed foods' problem. None of the sugar replacements can be made in your kitchen because they need to be 'refined' way more than cane sugar.
Sugar is a massively processed food, and it's subsidized to make it artificially cheaper. It's really easy to spot new threats, but we it's hard to recognize the dangerous things we do every day.