"People" is doing some heavy lifting here. There are some fringe people on trying to push that but most people I see are trying to explain that the main problem with obesity is that it is a food supply and class problem.
A lot of people are angry about the fact that the US spends the most on healthcare, but we don't actually live that long - with the implication that healthcare here in the US is a racket just stealing our money and not helping us.
But, why don't we live very long, compared to other people? A big reason is probably how fat we are, and how little we take care of our bodies. The best health care system in the world won't be able to fix you if you've ignored doctors orders to lose weight for 30 years and then have some health issues associated with that.
So, while people aren't explicitly saying "being fat is great", they are implicitly saying it, by pointing to something other than our own lifestyle choices as to the reason why we have bad health outcomes relative to the amount we spend on healthcare.
"Fat acceptance" is actually quite popular. It's not fringe. Fringe is being a furry. The entire medical field walks on egg shells because of so called "fatphobia".
You also say fringe is being a furry as if there are 10 or 20 furries and not millions of them.