First of all I agree that you have to be able to accept yourself as you are. If you don't, you may lose the weight but still won't be happy with your body. That said I don't agree with people knowingly making themselves fat. But before you start the fat shaming, which never works, you should consider whether an overweight person has an underlying medical condition. Though I've heard people mention underactive thyroid as an acceptable reason for being overweight but what about arthritis? If you can't move and have to rely on convenience food like I do during a flare up with my RA, of course you're going to put on weight. That is just one possibility but I have read a news article about five years ago that about half of people who are overweight/obese have an undiagnosed health condition causing the weight gain. So before having a go at a fat person, encourage them to visit their doctor first to rule out any health problems. There are many reasons a person might be fat and not all of them physical.
In short, you need to be body positive in order to lose weight otherwise nothing will change. In short there should be more help for overweight people to fight the reason that they are fat, be that a health condition or an unhealthy connection to food.