Well, the conception is that you can't DO anything about race and gender, so you have to accept people for what they are. Ditto with physical handicaps, birth defects, mental issues, etc. 35 years ago autistic kids were sent off to group homes, now they have parades for them!
Society is just starting to accept that sexual orientation may just not be someone's choice, so yeah -- we are starting to accept gay people now too.
But fatties? Sure it may be a genetic tendency but calories in < calories out. It's not rocket science. Get off the couch! Stop going to McD!! It's OK to bug us because we're doing it to ourselves.