If you believe that only scientists have the ultimate ability to define reality, then their failure with regards to calories in/ calories out, so far must be for you the definitive word on weight loss (WL).
If you think that this group are as capable of misjudgement and failure the same as the rest of us, then it follows that you don't believe that weight loss must necessarily consist of discomfort, pain and abject failure.
If you don't take them to always know everything, then you might have taken more note of the fact that the human body is perfectly capable of shedding weight whenever it feels like it, which unfortunately for lots of us, doesn't tend to coincide with our attempts to bludgeon it into submission.
If your instincts are not that they are as far as human knowledge could possibly go, then you do not think it's even close to impossible to put this whole sorry debacle behind us and simply move on, to better ways, chastened and perhaps more sanguine.
People want and need a way of lowering their weight, regardless of whether others like this or not. People at the higher end of the weight range, who've not allowed their weight to stop them mentally from doing things, but feel it does sometimes impede them physically, need a safe and effective way of reducing weight, and they cannot be shunned because some chose to make an ego issue out of it.
I also don't accept that the desire to be a certain size is purely down to the forces of oppression, obviously that has an effect, but moreso our innate sense of agency, desire for control and self-mastery.
Those who set their vanity against the desire for weight loss, regardless are playing a game of emotional blackmail that they will probably lose. Why should other people's desire to be slim or slimmer upset you if you're OK with yourself?
What I will add though is that wanting to be a lesser size is not necessarily a bad thing, how unhappy you decide to be about being fat, is your choice. If you are desperately unhappy about fat, then you are likely to have made this choice many many times.
That's also agency.