Marilyn Wann is a longtime fat activist and weight diversity speaker, author of the "FAT!SO?" book, and creator of Yay! Scales. The opinions expressed in this commentary are solely those of the author.

(CNN) By including Amy Schumer in its plus-size special edition, Glamour magazine not only touched off a minor uproar earlier this month, but it also revealed something important about America today: Anyone can suddenly be fat.

Glamour listed Schumer's name on the cover as one of the "women who inspire us," along with people whose bodies fit the magazine's theme. Schumer chided the magazine in an Instagram post -- "not cool glamour not glamourous" — with the rest of her response toggling between a call for weight freedom and an attempt to disavow the idea that she be considered fat herself, ("I go between a size 6 and an 8").

Social media went wild, Glamour editors tried to smooth things over in tweets, and a new round of discussion on body positivity took off.

And why are people so concerned? Let me explain. The line between fat and thin shifts. Society "decides" for us. The same person with the same body can get different responses to that body in different situations. You may be reading a magazine and learn that you're fat, or get the signal from your doctor, or when looking for a size in jeans to try on. You may get the word when you're interviewing for a job, visiting (unhelpful) family members, going on a date or flying on an airplane.

Even the government changed its mind on the issue in the '90s, declaring 25 million Americans "overweight" overnight. So the great weight divide is hardly a hard and fast truth.

Fat is a floating signifier. It can attach to anyone at any moment. Ask Amy.

But why do we care what anyone weighs? Well, the stakes are high when being thin or fat determines whether you'll be loved, respected, hired, promoted, dated, married, able to travel, buy clothes, see people who look like you in mainstream media, get unbiased medical care, and count as a person -- or not. (And these are just a few examples.)

This is why when a magazine slips a thin person into its rare issue focusing on the so-called "plus" sizes, it's news. People rush to re-establish the fat-thin borderline.

Society is preoccupied with maintaining a hierarchy of pounds and sizes and goes to great lengths to provide scientific justification for it. But this is becoming increasingly unconvincing. (Just Google "obesity" paradox or Health At Every Size to see why.)

people of color, poor people, When internet trolls claim their anonymous attacks on people because of their weight are motivated by concern for health, it's time to redefine our ideas about well-being and who is allowed to enjoy it. What's more, weight bigotry especially targets women disabled people , and LGBT people . So if we care about social justice, we need to be bigger lovers, not biggest losers.

Kudos, then, to Schumer for affirming fat people's right to exist and criticizing Glamour for moving the thin-privilege horizon below her size.

But what if she had said what I've been saying for more than two decades? What if she said, "So what?"

She made a good effort in that direction when she tweeted , "Bottom line seems to be we are done with these unnecessary labels which seem to be reserved for women." (Although I would add that men and people of all genders are hurt by weight labels, too.)

It is absurd ( and surely unprofitable ) that clothes in most stores stop being available at the sizes most people are. ("Our plus sizes are available online" is not an answer, it's discrimination.) When we're in fitting rooms, do we really believe that pieces of fabric can't possibly be cut wider but our bodies should be repeatedly reshaped (on the unmerry-go-round of weight loss and regain)? We are the judge of any garment, not the reverse.

No, it's not flattering when mainstream magazines think the majority of women should be grateful for an article or a special issue that mentions fashions we can buy.

That's why I also offer kudos also to statistically average-size model Iskra Lawrence for her largely unapologetic comeback to an internet hater this month. He was so distressed by the sight of her that he claimed his entire country's health system would fall apart from fat people eating potato chips. She posted photos of herself in lingerie among bags of chips and a slo-mo video eating a potato chip then giving the camera the finger. She dedicated these posts to "anyone who has ever been called FAT."

What if being called fat — or actually being fat — isn't the end of the world it's been made out to be?

It's time to stop worrying about where we are on the weight hierarchy and start wondering how we'll be remembered for what we did (or didn't do) to make the world a better place for people of all sizes, colors, genders, classes, physical abilities and sexualities.