I have no earthly idea how you can dispute this as both science and anecdotal evidence confirm this, but there are many that think it is too simplistic or requires too much discipline. So they believe the latest fad diet is what will work best... when there is a reason it is a "fad diet". It isn't sustainable, long term. (second point is that most people who engage in these fad diets end up eating less calories anyway, so they...shockingly, lose weight)

To your point #2, I was prepping for a Men's Physique competition and ended up getting down to ~1,650 calories per day (175g P, 35g F, and 150g C) but compare that to a guy I follow on Youtube who finished his cut closer to ~2,200 calories (don't recall his macro breakdown). I was so jealous! That is like a whole additional meal for me. I remember watching him be very real about dieting to get down to that low of a body fat percentage and how miserable he was feeling. In my head, I was going crazy because I felt the exact same way but was eating nearly 600 calories less!

Each individual body is very very different.