From the tribal point of view, a man who cannot keep his women under control is weak, the same as a man who tolerates being "dissed". Being weak invites others who might want to take your stuff, or otherwise "punk" you. Somebody in a lawless environment cannot afford to appear weak or ridiculous, because that makes him vulnerable. The only way out is commit some act of violence (preferably against a safe target) to restore your "street rep". (And my use of inner-city slang is deliberate, because similar dynamics apply there)
That sums it up really well. Literalist Islam has impeded cultural evolution. In the 21st century millions of people behave as if they were fighting for existence out of a tent in a desert.
Speaking of cousins, marrying them generation after generation hasn't helped, either.