Because people (who don't know what they're talking about) respond with statements like "you can cure Diabetes Type 2 with diet and exercise", and

- That's false. For _most_ people, you can prevent the symptoms of it with those, but not all. Nor does it _cure_ it, it prevents it from presenting symptoms. The same way that avoiding a food you are allergic to doesn't cure the allergy, it just prevents it from impacting you

- It's insulting to a lot of people that _are_ eating and exercising well, but still battling with Diabetes Type 2

It's wrong and it's insulting.