"Violence is the last refuge of the incompetent". -Isaac Asimov
.
Since god more times than not used violence and force, or the threat thereof, to get his way....well, you be the judge as to why.
.
"Men, in order to do evil, must first believe that what they are doing is good." -Alexander Solzhenitsyn
.
What better way to get people to commit any atrocity than to convince them god said to do it??