Try actually counting your calories over the course of a week.
This doesn't actually refute what the OP was saying, which is that he could eat as much as he wants without gaining weight. Presumably he simply wants to eat less than many people.
Anecdotally, I find this to be true. Some people simply seem to "know" how much they need to eat to maintain a healthy weight on some instinctual level. It's not that they magically make the calories disappear, it's just that they feel satiated at appropriate levels of caloric input with respect to their physical output.
The Biggest Losers clearly lack this characteristic, and the way in which they lose the weight boot-camp style doesn't seem to impart that ability upon them. Some of us will always simply have to use other means to manage input and output if we want to regulate our weight effectively.
The real question is: Why are people like Kenji satiated at an appropriate level of calories while others are not?
And I think the answer is going to be a complex mix of physical, psychological, and societal factors.
Eating three meals a day at about 2,500 calories for a few weeks, and my body will adapt to feeling full at those portions.
Upping that to 3,000+ calories a day when on a bulk, and the first week or two are difficult, but then I adapt and feel hungry if I eat the smaller portions I used to eat.
People gain weight when they gain muscle, and heavier people by the mechanics of supporting their weight seem to gain and hold muscle more easily than lighter people. More muscle mass has been associated with better health outcomes despite other factors.
I've also read that it's not being fat that's bad for you, but getting fat. Some people are unable to shed subcutaneous fat they gained at one point in their lives and carry a stigma of being fat despite being otherwise very healthy, even in their diet and lifestyle. It's a common idea that not shedding that kind of fat is a problem, but it probably isn't as much as people believe.
Being apparently not-fat could also be an indicator of worse health if you generated corporeal fat more easily than subcutaneous. That's what's being referred to when they say "belly fat" and apple bodies being associated with health problems, not the love handles and soft flab. Many people who look healthy because they're not fat could be skinny-fat, have higher corporeal fat, and not take care to exercise or watch what they eat, thinking that their weight and apparent size are indications that they're doing everything right.
But in cases of obesity, I do see people cheating their diets, focusing on easier but less important factors like steps per day, celebrating their daily water fluctuations as weight loss, and otherwise coming up with endless tricks and reasons to justify not not-eating.
There are many people I've never seen eating, but their trashcans and purses always fill up with food wrappers. They don't count that 900 Calorie Starbucks because it's just a coffee, and Weight Watchers says that's 0 points. Or they didn't use all their points last Tuesday, so they can have a treat today, and probably tomorrow since that doghnut just made up for last week and doesn't count.
That's certainly a broken regulation system, but it's one within their capacity to change.