"It's OK to hate them because they deserve to be hated," is your argument. Look, you aren't always wrong, but there tend to be a few factors at work here. The thing about people is that we aren't just who we are in the moment, we're the sum of our experiences to date.

If you want people to change, you have to show people not only that there are alternatives, and how to obtain the alternatives, but lastly -- and most importantly -- why they should strive for those alternatives. If you're just a dick to them, it doesn't help anyone.

Judging someone for being fat is about like judging someone for not being born rich. Eating and exercise habits are taught very young, and are very hard to change. It's very rare you see someone who is obese who wasn't put on that path by their parents.

Rather than make disparaging comments, I'm sure you have a friend who you could invite out for a jog? Or over to your place for dinners once or twice a week? Not everyone has rewards wired in the same as you do, certainly if they are obese they know it and can do without your reminder, and likely they've struggled to lose the weight and just need a bit more support.

You can either judge, and feel smug, or choose to help a friend.