Rohr: Harris seems to have "glanced" over the 20th century where religiously motivated "slaughter" is almost incidental to the mega murders of "death by government". Aside from the usual suspects: Soviet Union, Nationalist China, Communist China, and Nazi Germany, each of which killed 10,000,000 or more helpless and unarmed persons, there are (in the 20th century) 204 other cases of "democide" by state and quasi-state regimes, and non-state groups. (Statistics of Democide)
(Democide = genocide, politicide, massacres, extrajudicial executions, and other forms of mass murder)
Harris: "...most of the people in this world believe that the Creator of the universe has written a book."
Rohr: Harris is a rather sloppy atheist. The above sentence references - even acknowledges - a Creator. A good atheist writer would have written: "most of the people in this world believe in a Creator and believe that that Creator has written a book."
But sloppy atheism aside, the only group I know of who believe God has written a book would be fundamentalist Christians. Catholics do not accept the authority of the Bible on its own. They should know since they are the ones who decided what would go into the Bible in the first place. Muslims don't believe Allah wrote the Koran. The Jews know it was their patriarchs and prophets who wrote the "Law and the Prophets". Hindus and Buddhists have sacred texts but there seems to be no belief that the text came directly from a deity.
Of course what Harris really means to say is that there are many people who believe that their sacred texts are divinely inspired and thus carry or embody a unique authority or mandate.