Not Sophie, but similar issues to a lesser degree, I want to respond to gist of this.

I have been overweight my whole life (due to various reasons, about 50% psychological, 50% sheer laziness.) Society seems to say that fat = bad. Any reason or contributing factors are "excuses". Until you are thin and bouncing around in a bikini on the beach, you are not human, you are an insensate blob upon whom it is perfectly okay to pass comment.

It's really an ingrained mentality in our society. Many of my friends and family have betrayed their feelings, implying that it is all just an excuse. Some have actually paraphrased this.

And as for my opinion on people who can't be bothered, I don't care. I'd prefer not to pass judgement on how they treat their bodies. A dietary or lifestyle change is voluntary; there may just be much greater motivation for different people (e.g. avoiding death from anaphylaxis.) In theory I could lose weight, I just have enough to cope with at the moment and would rather work on internal improvement.
Anyone who should change their diet/lifestyle gets lumped into leper box, and I can't deny anyone the privilege of being lazy.