If you do Google “obesity paradox” you will swiftly find that the studies were biased by not filtering smokers out of the studies. Smoking suppresses appetite so smokers tend to be lighter and leaner, but their negative health outcomes are caused by their smoking, not by their lack of obesity!
When you filter out cigarette smokers the paradox disappears: all things being equal, being overweight is not healthy. It may be significant that obesity rates have gone up as smoking rates declined: the anti-smoking campaigns may have fixed one health problem at the expense of creating another.
I agree that it is not helpful to shame fat people, and perhaps we can say a bit of obesity is a small price to pay for having healthy lungs, but it is not correct to say it’s OK to be obese either. It just isn’t. I don’t think that encouraging people to stay fit and lose some weight amounts to “dehumanising and pathologizing” fat people.