It's frustrating, as Type 2 diabetes is 100% manageable through diet. You don't even have to exercise, just eat healthy. Today, with the use of continuous glucose monitors, you have all the data you need to make informed diet decisions - you know exactly what "eat healthy" means for your body.
Most people don't actually say it out loud, but this is all directly implied by the "personal responsibility" retort that is wildly popular among people who don't actually suffer from a given malady, in response to attempts to address it collectively.
However, I dont agree with your supposition following from that.
I think that obesity is a symptom of a cultural problem worth solving, not an individual moral failing, and there are better ways to learn than death.
There are lots of things in our culture that result in physical and mental sickness. It is good to treat the symptoms, but we should also pay attention to the cause.
Culture operates both at the individual and collective level. One can not exist without the other. One can not change without changing the other. Personal beliefs and actions shape collective culture, and culture shapes personal beliefs.
It is a disinvitation to solutions, and the rest follows naturally from that. I think a lot of people are using this as a thought-terminating cliche without actually considering how hostile the stance is.
A widespread lack of individual agency and self-determination is both a cultural problem and should be viewed as a call to action.
The question of why this is the case and what we can do about it is the interesting part.
People do have personal problems. Ignoring that is like blinding one eye before assessing the situation
That was practically the consensus social position forty years ago.
We didn't have an obesity crisis. Now we have an obesity crisis. Did the human race just become less responsible? Or are they enduring a new, situational, societal-level problem that affects many people collectively based on the socioeconomic & cultural conditions they were born into? Conditions that didn't exist 20,000 or 1,000 or even 60 years ago.
This is a longstanding conservative trope that excuses us from dealing with any and all social problems because we don't owe anything to each other. It is a declaration of social atomization.