New York City is "walkable". Yeah! Try walking from Queens, where I grew up, to Brooklyn. Then walk from Brooklyn to Manhattan. You'll be might tired after a couple of days of "walking".
Heck, try walking from midtown Manhattan to the downtown financial district. It can be done but takes a l-o-n-g time.
Most of the other cities on his idiotic list are also not "walkable". Only their downtowns might be.