Um I am aware Kobe Bryant is not a grammarian by trade but throughout the 90 minutes of Spike Lee's awesome doc Kobe Doin' Work (premiered Saturday on ESPN), he used the phrase the reason why like 30 times. It was distracting. See, the term why is embedded in the word reason, so the reason why is redundant. Retarded ESPN analyst Mark Jackson is particularly Cathcartian in his triple redundancy when he says The reason why (Jeff Van Gundy rocks) is because (of his wit and unsteady confidence). I don't know (why/the reason that) Jackson is paid to talk to people.
Anyhow, Kobe's done a lot for me so consider the usage advice free of charge. Don't mix why with because or the reason that. Keep that shit separate. Think of them as heavy guitars and rap. Or your cake and me. Or the once-great Bjork and the always great Carcass. Actually wait no that song was titties! Crank it (above)!!