TiA? I'm been on the actual blogs, by blogger proclaiming they are part of HAES, saying what i just said.

Only if you wildly (and likely intentionally) misrepresent what they're saying. But let's say you're right, you've found some misinformed person who has a blog on the internet - so what? The principles of HAES literally reject the idea you presented above.

They also claim about thin privilege.

That's good, it's a real thing.

Seriously, look at linda bacon, her book (literally, health at every size) says fat isn't a problem, that you can be healthy and obese.

Only if you're willfully misrepresenting her position. If you read her work you'll find that she argues that we should focus on health rather than thinness, and points out that there is no reason to assume that being thinner means being healthier (which is just obviously true, for example, someone who eats right and exercises well but is slightly overweight is going to be healthier than an anorexic).

HAES turned into fat activism long ago

Again, you say this like it's a bad thing. Even if it has, so what? It's a good thing to do what you can to help groups that have been discriminated against.

Are you sure you're in the right sub? I think you'd be better suited to TRP...