A phenomenon not limited to dieting.
Considering it's a societal wide problem, society at large ought to care about resolving it. It's incredibly expensive otherwise to treat chronic, lifelong obesity.
I do see a lot of people ITT who were accused of doing so but who aren't actually doing so.
And I've known quite a few people who get really annoyed at constantly having to hear about how impossible it is to do things that they've personally actually done.
obesity has a large hereditary component. important genes associated with obesity are expressed in the brain.
is it impossible to live with constant hunger and its consequences? no, likely not, but it's not really a big mystery why millions of people fail to do so.