I'd be confused as heck if I was a newbie and some text like that appeared on my new Wordpress installation. Yeah sure we all now know that they're just lyrics to a song, but new people won't, and if that's the first line that appears, it doesn't give a great impression of what Wordpress can be.

You don't need to remove the offensive lines though, it's part of an old song. Just clarify what it is so people don't get confused in the future.