> a company producing sugary snacks and diabetes pills does not force or even encourage over consumption of sugar
First of all, it is going a bit far to say they don't encourage over consumption of sugar. Nestle dropped a couple of billion on advertising last year [1], and that is primarily sugary food, or at least food that's broadly unhealthy.
Secondly, what about the tobacco companies? They did not force anyone to consume their products either; but with strict limiting of their marketing, especially to young children, the rate of smoking has gone down a lot in the States.
Studies show that willpower is a limited resource [2]. If you are being assaulted on all sides by a barrage of advertising, cheap snacks on display, and have been marketed to from your childhood, you are going to have a much harder time abstaining from these products.
I understand, or at least guess that you are putting forth a point of personal responsibility here – "Hey, don't eat those Hot Pockets, and you will be all good". But there are a ton of obstacles to that. These large food companies have pretty much ensured that most "convenience" stores carry only their products, and have little to no fresh produce or what you would consider "healthy" food. If you live in a poor neighborhood, a lot of times the only place that sells produce is located really far away, like 5 or 10 miles.
Thus, for some people it is clearly easier to eat healthy, and maybe some of that is on account of their socioeconomic class, current health, etc. But extrapolating that to all people should be a bit more nuanced, and maybe these companies' marketing should be a bit more regulated.
------------------
[1] http://www.statista.com/statistics/286531/nestle-advertising...
[2] https://www.apa.org/helpcenter/willpower-limited-resource.pd...