People seem to be completely uneducated about why and how someone could become overweight and then have difficulties dealing with it.
Aside from things like compulsive overeating and BED there are other issues, like the fact that it takes time to learn about food and how to take weight off! Yes, eat less and move more sounds simple but if you're eating refined carbs and junk all day if you simply try to eat less junk then you're going to be starving. Beyond that, food and nutrition is confusing and people have many opinions on what is 'healthy' for you.
It's just sad. People really do think overweight people are weak-willed and care nothing for their own health when it's usually the opposite. And you can't know if an overweight person is in the process of losing weight or changing their habits.