Thats why I said earlier that this is an evasive manuever. Throughout the middle ages, and today, islamic socities have had punishments for apostacy. Up until the 20th century, it used to be death for males, and imprisonment in a dark room for females until they repent. Now you can keep saying that it is not part of islam because it is not mentioned in the quran, but in practice it has always been enforced, and muslim scholars have always supported it. And it is a fact that apostacy carries penalties in most muslim countries even today, by law. That has been the consensus of most muslim scholars and jurists, throughout the ages, and these are the people who set laws for the people. You can pick any muslim society you want, whether saudi or iran or afghanistan today, and historically. Read the wiki page for how it has been through the ages:
Apostasy in Islam - Wikipedia, the free encyclopedia