I wouldn’t say that it is inexplicable. There are many high profile (ish) Twitch and YouTube accounts that feature Day Z content.
I’d say there are also relatively few games like it where randomness and organic player interactions are a huge factor. Plus there are many play styles like the solo runs (RunningManZ type content) or heavy PVP with teams and base building (Nezar type content).
There are also a ton of mods because the game is a “mature” ecosystem, so it keeps growing in weird and unexpected ways. Kinda like CS 1.6 did back in the day.