There's a Calvin & Hobbes comic in which Susie, Calvin's neighbor and schoolmate, sees something down by a pond and asks Calvin if he'd like to see it. Not wanting to validate the value of what she has discovered, Calvin indicates derisively that it's not of interest. Susie stalks off and Calvin sneaks to the pond to have a look. Susie catches him and essentially says, "gotcha!"
There have been numerous comics, stories, and performances depicted children in which one essentially says of another's possession, 'I don't want one. It's not so great.' In such cases, it's clear that the speaker thinks that it really is 'so great', but is trying to diminish the value of whatever it is in order to cope with the sense that it is beyond his or her ability to acquire it. A lot of people mistake this for envy, and while there may be an element of that, it is more about finding a way of balancing their despair with what they view as a cold, hard, and limited reality.
No one is immune from this. In the past, I have been guilty of it in ways both big and small. When I didn't fit in the bath tub due to my weight, I used to tell people I didn't like taking baths and that I didn't care about having a deep bath to soak in. I even convinced myself that this was not such a pleasurable experience that I couldn't partake in. Now that I can fit in the tub, I have to admit to myself that it's not only relaxing, but deeply and satisfyingly warming on cold evenings.
One of the most pervasive messages that people spread about something not being of value because they have concluded that they can't have it is having a life partner. They say marriage is nothing more than a loss of freedom, a life in shackles, and endless and unfair compromise and suffering. I never told myself such negative messages, but I did say I didn't aspire to being married. That was, in part, because I grew up having a very bad marriage role-modeled in front of me, but it was also because I thought I would never be wanted by anyone. If I couldn't have it, it wasn't worthwhile for me.
Unfortunately, most people aren't content to say that it's not worthwhile for them because they can't have it. They say that it has no or little value for anyone because they can't have it. I talk a lot about control, and this is something many people have concluded that they can't have in various areas of their lives. And, if they can't gain it, it can't be had by anyone and therefore should neither be sought nor desired.
This message is pervasive in the fat acceptance movement. There is a steady drumbeat of "can't lose weight, don't try." There is a constant trotting out of some dubious statistics about dieting and a 95% failure rate to the tune of many actually gaining more weight. These numbers may or may not be true, but that is a failure of method, not the value of losing weight. However, fat acceptance is populated by people who have tried and failed, tried and failed, and tried and failed. They can't have permanent and effective weight loss, so it has no value (i.e., no positive health effects that cannot be gained by healthy lifestyle without weight loss) and they can't do it so it can't be done by anyone (e.g., the "95% failure rate"). If they can't control their relationship with food and subsequently their weight, no one can, and they don't need to.
Frankly, I don't care what people weigh, but I do care about quality of life and I believe that you can't be happy unless you can move closer to who you want to be. If you can't draw a line between who you are now and who you would like to be in the future and start to make progress along that path, you will not be satisfied with your life. There's a word for people who can't move along and realize their goals. It's called stagnation. You can stamp your feet and insist that you are just great the way you are and that wanting to have more control is neurotic and destructive, but you're only succeeding in fooling yourself (if that). Harnessing chaos (including our own chaotic relationships with every aspect of our lives) and turning it into something organized, creative, and harmonious is what humans do. It is the essence of our nature and it is harder to do it with ourselves than nearly anything else in our lives.
Control is about avoiding stagnation. It's about not being trapped in your own head and body and being unhappy with where you are. It's also about not spending all of your time and energy convincing yourself that you are happy staying right where you are because you feel there is no place else you can go. It doesn't have to be about weight, but often in fat acceptance circles, that is pretty much what it is about. They preach a message of "can't control, don't try, just accept". I don't like that message, not because I care about people being fat (I truly do not), but because I think that the message should be that you can be what you want to be, not simply be told you'll never have enough control to be anything else. That goes for everything, not just weight.