I agree, OP.
I was in a body positivity fb group for a while years ago. The group was for everyone who didn't feel they fit 'Western Beauty Standards' for any reason.
I never posted, but initially, it was really supportive to those who did and it was uplifting just reading the support and kindness towards others regardless who posted or who responded. Women who had ventured to the gym despite feeling self conscious about their wobbly bits were championed. Women who had avoided being in photos with their children bravely posted a holiday snap and were loved for it. Women who didn't know how to eat healthily had tried a new recipe and shared it to congratulations.
No achievement was too big or too small. No woman was too big or too small.
I left when I realised it had morphed into something very different indeed.
Eventually, the only acceptable body size on there was obese/morbidly obese. The only acceptable level of exercise was none. Every common or garden overweight/mid sized women who posted was pilloried and woe betide you if you were slimmer and just lacked body confidence. I remember one woman who posted a few months post partum with a crepey belly and wobbly thighs who was clearly really struggling with the change in her body and early motherhood. But because she was a size 10ish, she was absolutely ripped to shreds and bullied from the group.
Eventually, no one was safe on there really, even the acceptably large women who posted that they wanted to go swimming or join a gym for fitness or to lose weight because they wanted to TTC or because they wanted to be able.to run around the park with their children or see their children grow up were attacked as traitors and mocked for believing the lies and propaganda.
Only a complete rejection of healthy eating and exercise was accepted. Only a complete rejection of self care was championed. Anyone sharing that they'd 'fallen off the wagon' diet and exercise wise was celebrated and welcomed back into the fold. Only complete submission to the bigger is not only beautiful but better in every way mantra was acceptable.
Nothing other than being very overweight was even represented anymore. No acne scars, no thinning hair, no disliked facial features, heights, nothing.
It was vicious and, tbh, irresponsible. I can't really convey how toxic it was in the end.
I don't think body positivity had been about actual body positivity for a long time.