United States, obviously. Article makes zero pretence being about anything other than that and it's stated right there in the opening paragraph: "among America’s youth".
American drivers tend to be extremely aggressive towards cyclists. Long distances mean you will get tired and/or sweat. Lot of 2 lane roads without shoulders or sidewalks makes cycling on them scary.
I do cycle (normal bike). These are some of the things that I told myself that kept me from getting into it when I was younger.
On fat Americans: at the time and still I'm likely a 99.9%er cardio wise, and I still had the concern about being sweaty. I wasn't exactly trying to smell bad during lectures.
Ob ebikes not being tanks: Going 20 in a 25 is a lot less scary then going 8 up a hill where cars are BLASTING past you. Lower effort also means you can spend more brainpower on spacial awareness, when you are gassed you tend to notice less around you.