He is wrong. Man (humans) are actually made to run, that is our actual primary moving function to walk and run for hours.
Google sometime “Persistence hunting”. It is done today by a few Masai Warriors in Kenya but it was very commonplace at one time. We don’t have the speed to catch a gazelle, but we have the ability to wear them down.
We were not build to run in the shoes the big shoe makers make and on asphalt. Therein lies a key difference.
We have several aspects of our bodies that are made for long distance movement, including sweating for cooling, which is much more efficient than panting, like a dog. We have a tendon in the back of our head that promotes the movement of bi-peds, not unlike a horse. We can go long distances without needing top stop when we are fit.
Another key difference here is that average person in a city does not get fit, wears shoes that bind the feet and are heavier than optimum. Runners needs to be very thin, healthy, but thin. And fit.
This is why we can run marathons and ultra-marathon but note that an ultra marathon is “off pace” enough that they don’t have a 20-mile wall like an asphalt-running marathon runner. They have a soft surface, and a pace that works.
It is most four-legged animals that are not built for long-distance running, they are built for short sprints. Cheetahs go 60 miles per hour for a few hundred metres and then are done. So is the gazelle, zebra, dogs….you name it.