Burning gasoline for useless digging actually is bad for the environment. And it might not be amazonian rain forest that we're talking about, but an "empty land" is better left untouched than slaughtered like this.
How is this any different? It's entertaining plenty of us, it's less fuel than a race and less land than a racetrack, and maybe we'll learn something in the process. Maybe innovations in moderating the futility of online comment systems. ;)
Edit: Not sure why I'm getting downvoted, those three vehicles are burning diesel...