The guy in the videos (trowan, or whatever his name is) is disingenuous to the point of dishonesty.
The back-of-envelope calculations look reasonable, AFAICT, but:
1) Sondors' site doesn't say anywhere thatI can see "80mph sustained", only "80mph top speed". Big difference, and trowan repeats this several times.
It's quite rare that any vehicle vendor quotes a top sustained speed (airplanes aside), but if they do, they usually call it "cruising speed" and give a separate top speed. That should have tipped him off to double-check, since he's clearly not a newcomer to electric vehicles of various types.
2) He pretends surprise that the max range claim isn't for the max speed, whereas it's the standard practice that pretty much every maker of every electric conveyance from the single-wheel scooter onwards. Very regrettable, but standard.
I think it's much more relevant and concerning that Sondors don't have a production-intent prototype yet (even if handmade) -- surely after selling 100K bikes they should have enough money to build one, even if not to homologate it?