In the UK, we are, and always have been, biased against fat people.
There is an inbuilt Pavlovian response in almost all of us, that subconsciously registers a fat person as either stupid, or lacking in self-respect, or both.
For me, the notion of people 'celebrating' obesity is absurd, because it is dangerous to health for anyone to be obese, there is no 'good way' to be massively overweight.
When I see people in the media making a big deal of being 'proud' to be fat, I think it sends out as much a wrong message as it does to demean obese people.
I would suggest that discriminating against fat people in terms of employment, is as fundamentally wrong as discriminating against colour or religion, but there are already protection rules in place regarding discrimination without valid and appropriate reasons.
I am all for tolerance, but the notion that obesity should be effectively encouraged in this way, I believe to be a wrong move.