My understanding is that more research is pointing to obesity as, in some sense, a precursor/reaction to the onset of type 2 diabetes rather than type 1.
Once you get to quite obese you're dealing with physiological factors that make losing weight medically difficult from behavioral changes alone. It also makes the chances of "yo-yoing" the weight higher as well. At that point the treatment for obesity overlaps with the treatment for type 2 diabetes.
Yep, it definitely is! I mentioned type 1 because I have it.
As a contrast -- the point was that nobody judges me for having type 1 the way they judge people for having obesity.
As an aside, I notice that sort of "lifestyle/willpower" type framing in discussions about type 2 also.