It is supposed to be a joke, as the entire band's music is everything but about being serious. I think it's a great rendition, and they set the way for Green Day's WATC. Although the latter remained in the Queen tradition, by providing the piano.
So what if the guitarist, not being the lead singer, sings? He does that on stage as well (the last song of a gig), I haven't seen many do that (doing the vocals for a song)
The reason for such a late debate is that I only recently saw the video and wanted to see if there're any reactions on Queenzone. It's punk, "dude"!
You can be anything... anything you think that you could ever be