I haven't read the whole thread, so this is my response to the OP.
I do agree that there is an inconsistency, but weight issues are far more complicated than just people being lazy. The food that we eat is so heavily processed that, unless you have a lot of time on your hands and can cook everything you eat from raw, locally produced foods, you don't really have a choice in how healthy you eat. The biggest problem with diet is sodium content because it is being used to a huge extent in almost all processed foods.
I do respect your opinion of the inconsistencies in political correctness, because they do look odd to the casual observer, but I don't think you understand the impact of this on women. You talk about facebook pages like 'big women are beautiful' and cast them as simply championing their weight.
http://1.bp.blogspot.com/-IdNkLW9rbes/TaAvnHc2tPI/AAAAAAAAACw/D3q4-q9ttvM/s320/photos-of-thin-and-fat-girls.jpg
Notice the name of that picture is 'photos of thin and fat girls'. That means the one of the right must be the fat girl. Women have a much larger range of body types than men and in this culture anyone who is not rail thin is seen as being fat or obese and, as far as I can tell, they tend to hold onto weight for biological reasons that do not exist in men (such as constantly fluctuating hormones caused by menstruation). The woman in that photo is not fat, but she will be called a fat girl because she does not fall into an extremely narrow view of what is healthy for a woman. If a man had the exact same body size as that woman he would be considered normal.
There are some people that revel in their weight, like anyone who shops at this site for any reason other than being a skinny hipster: http://www.fatguyshirts.com/
My point is that weight issues are far more complicated than smoking issues, and anytime you talk about weight you are necessarily talking about gender inequality because of perception differences in what constitutes as fat or thin. You are also necessarily talking about class issues because of higher obesity rates in poorer people (because of the aforementioned processed foods) and, by extension, a racial issue because of the higher percentage of minorities being impoverished.
Relative to weight, smoking is a simple issue. I haven't done the research on this but in my experience most people start smoking due to peer pressure in their early teen years and I imagine that in some cases this is entirely unavoidable for the individual to have any sort of a functional life (in those cases where gang mentality is prevalent, for example). The biggest difference between weight and smoking, though, is that despite smoking being a chemical dependency it is easier to quit because it doesn't really require any changes in lifestyle. I don't mean to belittle anyone's accomplishments in quitting, but I have met many more people who have quit smoking than people who overhauled their entire lifestyle to lose weight.