And the counterpoint is that most people aren't able to do that much exercise. Because it's A LOT. Basically full time athletes or highly physical workers. So that excludes all people with a sedentary or only partially physically demanding work.

Sufficient is a lot. If you eat a fast food meal (burger, fries, soda) above maintenance you're looking at half a marathon to burn that off. And most people aren't pro cyclists that are able to sustain 400 watts+ for a hour.

Sufficient is a lot, but it’s nowhere near as extreme as that example makes it sound.

That’s a half marathon for a 150 lbs fit person, running efficiently. A 250 lbs person who is a little out of shape will burn that in a 2.5 hour walk.

Obviously 1300 calories a day above maintenance is extreme for most people, but energy expended scales non linearly with weight. There are also a lot quicker ways to burn calories than marathon running.