Add the fact that upwards of 70% of all marriages in certain countries are consanguine, going on for gods know how many generations...meaning that plenty of them are not able to function in modern societies because of mental defects, such as low IQ, extremely poor impulse control and low ability to consider the consequences of their actions...all coupled with a high sex drive and feelings of entitlement.
Reminds me that I need to find a shooting club and join. For reasons. And get my hunting guns.
While a lot of folks on APS are not fond of Islamic or Arabic persons (not referring to you, Viking), this is a legitimate concern. And personally, I do think there is a very strong correlation between Arabic countries, and Islam, high rates of consanguinity and general instability.
http://reproductive-health-journal.biomedcentral.com/articles/10.1186/1742-4755-6-1725-30% of all marriages in Arabic countries may be inbred, by genetic standards. According to above link, the LOWEST in the region was Lebanon with 12.8%. That means the lowest level of inbreeding is one tenth of the population. Some areas have above 70%.
There's a reason why it's banned in most of the world. Lower IQs, much higher physical defects, mental illness, higher likelihood of genetic disorders, etc. Eight countries had more than half of their marriages being consanguine. It's acknowledged as being a problem, but it has religious, historical and economic implictions. It's allowed in Islam, so bans don't have religious support. It's common for hundreds of years, so there's a strong historical tradition. And the desire to keep economic resources within the same clan (dowries and whatnot) provides an incentive towards consanguine marriages as well.
While I'm not saying banning consanguine marriages would fix all of the Middle East's many many problems, I would say it'd drastically improve the situation. Unfortunately, it'd take generations to repair the genetic damage. Cousin marriages were commonly practiced in Europe in middle ages. While I'm not saying it was the sole reason for promoting wars and general instability, it didn't help. It fell out of favor in 19th century, given a couple of generations, Europe is getting genetically much healthier.
I'm rarely the type of person that encourages legislating morality, but that has been a positive development of the US and Europe. Thankfully other parts of the world are also cottoning onto that.