Well there are other factors than diet. So you have quite a bit of people in the "fitness" community on e.g. youtube promoting "eat all you want", and they choke down pizza, hamburgers, etc. But of course those people are doing lots of exercise (or using drugs that prevent certain bad effects of excess calories, etc), have large muscle mass (which can help prevent cancer), or might burn of insane amounts of calories due to running, swimming etc.
So besides people with good genes being able to get away with bad habits, you might have people with good habits being able to get away with bad habits, so to speak. And in the case of some extreme people they might need to eat extreme diets involving pizza, hamburgers, etc, because they have insane caloric demands.
Anyway most people will probably eventually get fat if they do a "eat all you want, if it fits your macros" diet.