Why would anyone have to give a disclaimer? We’re not dealing the FCC here. You choose to give them, others do not. One giving disclaimers does not make that person superior to those that do not, and vice versa.
This article, though, is basically a giant disclaimer. Without it, you would simply be writing something to the effect of “People rallied to a woman who isn’t that fat who was called fat and it pisses me off. Would they do the same for someone as fat as me?”
It does feed into a culture of man hating, though. Which is typical for someone who links xojane articles, but I digress.
The difference between a woman who isn’t all that fat being called fat compared to a woman who is indeed very fat is evident in the degree of obesity involved. You can be fat and not be obese. You can be barely obese. You can be grossly obese. And so on. We’re talking anywhere between not feeling comfortable wearing little on the beach to getting skin infections due to skin folds. One of those isn’t that big of a deal, while the other is. Should it be the business anyone but the fat/not fat person involved? No, not really.
But we can, as humans, identify certain things that are clearly bad. Being obese is one of them. There are no health benefits to being obese, while the drawbacks are legion. Humans, though, react to all sorts of bullshit superficial things, things that have nothing to do with the observer.
There are legitimate concerns when it comes to things like public transportation, airplanes, or public health budgets, but that is usually highly abstract, and it’s hardly the reason why the woman snickered when her daughter said something mean about you.