Indeed...my research shows that Mr. Hitchens is one of the '4 Horsemen' of New Atheism...not a
surprising revelation that you'd choose him as your sole reference. (see link) Which leads me to believe he's not very open minded...or in any way, Balanced...when it comes to assessing the nature of Islam.
For your benefit in hope of severing your association with such a close minded person, I offer...along with the previously recommended book "No god, but God"...that author's Wiki Bio which shows he is truly 'Open Minded' when it comes to All Religions, but especially Islam.
If you're wise enough to accept my recommendation, you'll find that Muhammad's takeover of Mecca was instigated by the Moneyed Quraysh clans who were using the city as an enterprise to fleece the many small individual 'religions' and line their pockets, while abusing slaves and the poor...which greatly offended the young Muhammad...according to Aslan and other historians.
Unfortunately, Muhammad didn't designate someone to take his place, and that set the stage for rampant violence by others to fill the void...---> Sunni, Shia...etc. which continues to this day...but not everywhere. To understand the whole story, you'll need to take time and read the book...assuming you really care about this issue...and have an Open Mind.
Here's Reza Aslan's Wiki Bio...https://en.wikipedia.org/wiki/Reza_Aslan