Many metal/indie/rock artists are the same - they have their stage persona, which can often be very different from the 'real' person. Ozzy himself often said there was John Osbourne - and then there was 'Ozzy'. It reminds me of the late Keith Flint of The Prodigy and how everyone said was a lovely, kind, genuine, quiet person he was, as opposed to his on-stage persona. I think that's probably true for a lot of artists - it's a 'costume' (sometimes quite literally in some cases) which they don in order to become that stage performer.