Re: If Islam is a source of knowledge....
Probably one of the biggest strains on Muslim intellectual thought process and critical reasoning is the advent of Wahabi version of Islam.
Extreme obscurantist views propagated by the petrodollars, aided and abetted by Uncle Sam/west in the war against communism and their desire to secure supplies of sweet oil, it has contributed to the general decay in how Muslims of modern day can and should behave. When critical reasoning is restricted by edict of obscurantic scholars who are influenced more by their tribal customs and natural need to protect traditions, then societies are not permitted to think or act freely.
Whenever socieities have become subservient to extreme religious practices, they have suffered. We have the Taliban and Al-Qaeda experience in front of us, history is full of such examples in all religions.