Video is traditionally landscape because it is emulating movie film.
Movie film went from the mostly-square rectangle we know and love (4:3, or a full 35mm film frame with an aspect ratio of 1.33) to the various widescreen landscape formats (ratios like 1.77, 1.85 and even the truly stupendous Cinemascope frames ranging from 2.35 up to 2.6 aspect ratios) as a defense against the home television set, which was (barely) 4:3. Movie studios needed a way to put seats in butts, and realized if they ran the same 35mm film through the camera sideways and tweaked the optics they could print wider frames on the same film stock and give a new experience unavailable to home viewers.
Filmmaking techniques (two shots, over the shoulders, wide angle landscape establishing shots) adapted to the technology, not the other way round.
Digital has given us amazing freedom to ignore many of the strictures of the analog world, and maybe the best aspect ratio is the one native to the device and not native to our habits. Phone sales outstrip traditional desktop computers by a large margin, and the switch to mobile is only accelerating.
Also, the kid doing the recording? He used framing perfectly to capture the action and include his commentary in one well composed frame, and I don’t see any diagetic need for horizontal framing.
(Sorry, I don’t get to actually use my film degrees very often.)
