"Muhammads' military expeditions were defensive."
I don't know where you got that idea from. An imam perhaps?
May I suggest you read the biography of the 'prophet' and enlighten yourself. (see tagline for Free Book.)
I have started reading the pdf you linked to about the history of Muhammad, it is very interesting. I copied it to my computer and shared it on Limewire under the keywords relating to Islam. I think Americans have done a disservice to everyone involved by maintaining the attitude the Islam, Christianity, Agnostics are all flavors of the same food, and they really are not. I view the so called "Prophet" more and more as nothing but a succesful David Koresh or L Ron Hubbard.