Black I think you're discounting the Wahabi's sense of religious purity. I just finished "God's Terrorists" by Raj historian Charles Allen; his book follows the Wahabi cult in British India 1800-1853.
Osama is reading from the play book Allen outlines. Even religious nut cases have their "rules".
Yes, that should be interesting reading, but there have been many changes since 1853 - as previously mentioned, like the purity of the 9/11 terrorists.
Watch for the reports tomorrow on the contents of declassified material released today which contains Osama's instructions to "The Iraqi". It is likely that it contains information on missions "The Iraqi" is to carry out against the US outside of Iraq. Apparently proof of orders directly from Osama to someone in Iraq for attacks outside of Iraq. Something many liberals have claimed never happened. I look forward to learning the details.