The PEW study on the world's Muslims claims that far more than half of the South-Asian and Mid-east/North-African population believe in the death penalty for apostates. In extrapolating their genuine nature & international threats of said people, is it rational to take these conclusions seriousl

I don't know if you're cherry picking or not, but the executive summary reads exactly as one would expect it to read:

At the same time, the survey finds that even in many countries where there is strong backing for sharia, most Muslims favor religious freedom for people of other faiths. In Pakistan, for example, three-quarters of Muslims say that non-Muslims are very free to practice their religion, and fully 96% of those who share this assessment say it is “a good thing.” Yet 84% of Pakistani Muslims favor enshrining sharia as official law. These seemingly divergent views are possible partly because most supporters of sharia in Pakistan – as in many other countries – think Islamic law should apply only to Muslims. Moreover, Muslims around the globe have differing understandings of what sharia means in practice.

Overall, the survey finds that most Muslims see no inherent tension between being religiously devout and living in a modern society. Nor do they see any conflict between religion and science. Many favor democracy over authoritarian rule, believe that humans and other living things have evolved over time and say they personally enjoy Western movies, music and television – even though most think Western popular culture undermines public morality.

Few U.S. Muslims voice support for suicide bombing or other forms of violence against civilians in the name of Islam; 81% say such acts are never justified, while fewer than one-in-ten say violence against civilians either is often justified (1%) or is sometimes justified (7%) to defend Islam. Around the world, most Muslims also reject suicide bombing and other attacks against civilians. However, substantial minorities in several countries say such acts of violence are at least sometimes justified, including 26% of Muslims in Bangladesh, 29% in Egypt, 39% in Afghanistan and 40% in the Palestinian territories.

/r/statistics Thread Link - pewforum.org