Please keep in mind, I am not intending to create a deliberately divisive post, I am simply interested in asking a question. A little bit of background. I used to be a Muslim, but am far more secular right now. One of the things that caused me to have a sort of existential crisis was finding out that apostasy is apparently punishable by death in Islam. This ruling, even as a Muslim, made me very uncomfortable. I didn't agree with it at all, nor did I believe that historically, Muslim scholars always agreed with the idea that people should be killed if they left the faith. Anyways, I ending up learning a little bit about three men. Their names are Abu Isa al-Warraq, al-Ma'arri, and Ibn al-Rawandi. All of these men seem to have been either critics of interpretations of Islam that were prominent during their time, or they had left the faith, and were critical of Islam and religion in general. Yet, to my knowledge, none of these men were killed for their writings that were critical of Islam. All of them seem to have died a natural death. Al Ma'arri was apparently even loved by the people of the city he lived in. If this is the case, why weren't they killed for blasphemy of Islam, or apostasy? It seems that not every Muslim state or even not every Muslim scholar believed people should have been killed for their blasphemy or apostasy, but I am ultimately not sure about this. I am also aware that some supposed critics of Islam from these time periods may not have been critics of Islam at all, but accused of being critics. I believe it was Muhammad al-Razi who was apparently accused of being an ex-Muslim, when apparently all the work we have from the man is commentary on him from one of his most vociferous critics, but I am not sure about how true this for the other three men that I mentioned. So, as the question asks, how was apostasy perceived among Islamic scholars or even Muslim rulers throughout the years?
It’s been a couple of days, so mods have a mercy on me, but I do want to give it an answer. I am not a Muslim historian but I spent some of my early life living in an Arab country, and have been fascinated with Islamic history ever since.
Many of the scholars you referenced lived during the height of the Abbasid Caliphate, the largest economy in its time and a society that deeply emphasised education and knowledge. Many of these scholars were born Muslim but changed their faith and as you said, were not punished. But if modern (and radical) Islam punishes Apostasy? Well, religion changes, and none are more true then Islam. They were born into good living conditions and opportunity to make a profession of scholarship, and as they philosophised they began to turn away from superstition and towards secularism. But no-one cares, Why? What many forget about Islam, (especially the Abbasids) is that it heavily emphasised Freedom of Speech. There is a famous quote from Imad ad-Dean Ahmad (a cousin of the Caliph Al Ma’mun) who debates with a religious opponent and emphasise the fact that the Quran states there “is no compulsion in religion” (2:256), that is the basic translation I apologise if it is wrong. So Ahmad attempts to convert through reason and if his opponent refuses, he wishes God blesses him and shows him the truth. Ahmad insults his religion multiple times I should add, but still emphasises that it his right to speak his mind freely.
I always go back to a quote I remember reading when researching the Protestant Reformation, “If modern Christians saw what the Catholics and Protestants did to each other, they would be disgusted”. The opposite is true for Islam
Whether Muhammad thought Apostasy should be punished is difficult as most of his beliefs were written in the late Umayyad or early Abbasid periods, ranging in tolerance depending on who wrote them and when. Most Abbasid scholars simply say Apostates are non-believers who simply need to be shown the way again, however Umayyads would have seen them as traitors as their empire began to enter turmoil and they needed loyal allies.
I hope that gives you some answer, if you choose to return to Islam or stay Secular, I hope at least you understand that religion is heavily divisive not only because of its relationships but also its interpretation. To give one last quote from Patricia Crone, the late Islamic revisionist historian “as easily as the world of our grandparents become ancient history, the founder must resign himself to the fact that it only takes three generations for his life and works to be thoroughly reshaped”
I hope you all the best, and mods have mercy on this answer