In my opinion there are very very few songs with really good lyrics, conentwise that is (and no, I wouldn't count any of those you named, Urotsukidoji). But most of the time I really don't care, since, as 2H-Dragon put it: "Go read a book if you want some deep shiz."
There are exceptions, of course.
And Leedizzle is right as well. There's nothing that makes universally appealing music inter-subjectively stupid. From a purely subjective point of view I would call lots of it stupid though, but meh.
And to the two metalheads here: Metal is not better than rap. It's funny that you mentioned Sonata Arctica because I would say they're inferior to pretty much every rap-artist I listen to. Don't get me wrong, I like metal as well and the genre has produced some great music and what I said before certainly applies the other way around as well: rap is not better than metal. But I just don't like it when people dismiss a whole genre without ever giving it a serious try, or worse, exclusively listen to only one genre. Not that I would force anyone either.