Take a cosmetic feature considered undesirable in a given society. Pressure people into making their bodies more attractive to meet society’s cosmetic standards, and berate them if they don’t. Create an entire industry that pushes people to conform to this cosmetic standard. After these efforts fail and fail again, they declare an “epidemic” of a new health condition, using a common insult as an “objective” medical term. With its new medical authority, the same industry continues to enforce this cosmetic standard, though it’s now tied to moral imperatives in ways it wasn’t before. Stuff this term of abuse in nearly every health article you can find online—and those who complain are being unreasonable because “doctors use it.” And by harping on this cosmetically offensive feature, you have now pushed your hapless victims to identify with their outward appearances in ways that are sometimes counterproductive (but not nearly as counterproductive as the fraudulent, bullying medical practices that pushed them in this direction). And you continue to profit because people are worried they’ll head to an early grave unless they fit their society’s attractiveness standards.
If you’re defending the use of insults as diagnostic terms, you’re a bully. (And taking a lot of regular, well-meaning doctors and researchers for a ride because they don’t know what it really means.) If you make money off people’s insecurities based on a “condition” that serves your financial interests, you are a scammer. I have zero respect for bullies or scammers.
Forget “fat acceptance.” (It’s too identitarian and superficial for me, and you can’t fight superficiality with more of it.) Try for something broader: don’t be an asshole. That should be good enough.