This is really a hard one.
I don't necessarily disagree, though. They aren't refusing emergency or life saving operations, just routine procedures which evidence show are less effective and/or ineffective on people who are obese anyway.
This reminds me of my MIL. She is obese. I would say a size 18-20? Doesn't exercise and refuses to change her diet. Has been offered a free gym membership and referral to CBT. All refused.
Surprise surprise, she now has problems with her hip. She refused to go the doctor for about a year because "he will just tell me to lose weight".
Finally got to the point she couldn't walk up stairs. Went to doctor, who told her she needed to see an osteopath as well as lose weight. She refused to see the osteopath because he was make so went to see a female chiropractor instead. She was recommended six sessions and offered support to maintain hip and exercise it in safe, recuperative ways.
She will only go for three sessions because that's all she will get for free, and "why should she have to pay". She won't exercise because "they all just blame her weight".
The reality is a lack of exercise and refusing to address the issue, as well as carrying extra weight, is the problem!! No point in replacing the hip!!!