Have you possibly considered that some of these women who are obese also have an eating disorder and are trying to accept themselves to try to curb unhealthy behaviours and obsessions?
Now of course i'm not saying every, or even the majority, of obese people, have an eating disorder. Just like how not every underweight/slim/athletic person has an eating disorder.
BUT there is absolutely an opposite end of the spectrum where instead of extreme food restriction and control, there is complete lack of control over eating. Compulsive over eating, binge eating, both occur in bulimics too, but in these cases the sufferer doesn't "purge"(vomit) afterwards, in the way a bulimia suffer does, so there isn't a removal of any of the binged food and calories, leading to usually significant weight gain and being obese.
Unfortunately this end of the eating disorder spectrum gets much less acceptance, understanding and sympathy, even from medical professionals. You get labeled things like "greedy" and "lazy" rather than recognition its an illness. I absolutely understand larger people trying to accept themselves for how they are since the help is pretty none existent for these sufferers.
As for "regular" overweight people, if it makes them feel better about themselves, is it really such a bad thing? It may even help them to make healthy changes if they can accept them self as they are but want to make "improvements" instead of feeling they need to change drastically. Surely they will take it slower, go steadier, and be more likely to succeed as they wont gt as easily overwhelmed and give up thinking its too big a task.