Agreed on the part of not taking responsibility for your own unhealthy habits. Also, there is no doubt that biology realities are immune to political correctness.
However, I find the tone of the first comment (and your too, to a lesser degree) quite disrespectful. You seem to imply that people are full aware of what their unhealthy habits are, and what precise steps they need to take in order to change those for healthier habits. In particular, you seem to subscribe to an early modern model of human behavior that assumes everyone is 100% rational and if they engage in, let's call'em "unproductive", behaviors it must be because the person is wicked. This model of behavior is factually wrong, and to believe otherwise is to dismiss the whole body of knowledge of modern psicology (yes, from Freud on. I am aware he had a thing with sex issues, but at least he understood that, under a thin rational layer, the innards of human mind operate on irrational symbol manipulation and pattern matching).
What other people is trying to tell you is that you are not helping anyone by condemning the fatsos of the world. You gain nothing but to stroke your own ego, and don't seem to mind alienating other human beings in the process.