People talk past each other on this because for an individual it technically can work, and sometimes does, but on a population level, as extensively studied by people whose job it is to study that, it definitely does not work. Even with tons of regular attention from professionals and a cohort selected to have above-average motivation, it’s surprisingly poorly-performing (and that’s a crazy expensive level of intervention)

Think about how we describe contraceptives, medically speaking: a failure rate is tracked and promoted that’s the in the wild rate of failure, not the ideal-use rate of failure (which can be effectively zero!). The diet and exercise equivalent of a contraceptive couldn’t be sold, because its failure rate would be way higher than its success rate.

So “we” (people who’ve paid attention to the science on it) know it doesn’t work (on a population level), like for-sure definitely does not work, but a person reads this assertion of fact and goes “but wait it worked for me, this person must be dumb or something” but that’s not it. It’s two different perspectives on what it means for it to “work”.