My understanding of ISIS (mostly from a Muslim Arab coworker, so of course my "expert" could be wrong) is that they're "religious" in the same way Scientology is: they have all the trappings of religion, but it's all quite contrived. They emphasize whatever parts of scripture helps their goals and ignore the rest in a very obvious and transparent way that fools almost no one. It's not that they're murdering "moderate Muslims" per se, they're simply murdering anyone who speaks up about how evil they are, or simply speaks against them, whether on religious grounds or any other grounds.
I would argue that that's true of all religions, and everybody. If you can show me an entirely internally consistent religion and a person who follows 100% of those teachings exactly, I would be shocked! Everybody emphasizes whatever part of the scripture they want and ignore other parts. Some conservative Christians glide past the "Do not judge" part and spend a lot of time focusing on sexual immorality! Some liberal Christians glide past the many parts of the new testament that deal with sexual immorality and spend a lot more time with the "do not judge" part! That's just religion for you. Remember, even a religion as seemingly peaceful as Buddhism had adherents who really perfected the modern concept of the suicide bomber.
Personally, I was offended when President Obama attempted to define what true Islam was, and who was a true Muslim and who was a faker. How colonialist of him to attempt to be the arbiter and definer of native religion!
There are many other places in the world where IMO the problem really is religious fundamentalism, but those guys aren't raising armies and conquering vast territory. Even in Afghanistan it's just one tribe after another, not a united fundamentalist army.
I think you're partially right and partially wrong. The issue is that Islam to a very large degree overlaps with parts of the world that have maintained pre-modern tribal ties to a degree that most of us in the east and west are no longer familiar with. Thus, in Afghanistan, it's not that the fundamentalists aren't united, but that many tribal coalitions have been unified through fundamentalist Islam.
I think it's a mistake to confuse the problem with fundamentalist Islam in other parts of the world and other cultures with ISIS and the Arabian Peninsula.
I don't. We could have a nearly infinite discussion about the history of Islam, the history of the Middle East, the rise of the West, and the economic and social morass of much of the Islamic world. We would actually probably end up agreeing about a lot of these things! Militant fundamentalism used to be a part of Christianity, but was stamped out a long time ago. Militant fundamentalism in Islam has yet to be eradicated. If you think the trappings of Caliphate, the revival of the 'Uthman dinar and other potent symbols of early Islam, and the persecution of historical enemies exist in a vacuum, I think you're very wrong.
Have you ever heard a evangelical Christian Bible study or lesson? It's interesting. They will focus to an incredible degree on each word of the verse they are studying. They will talk about the word in the original Greek (or Aramaic, etc.) and its connotations, how it compares to other Biblical accounts, etc. We're talking nitty gritty minutia and some interesting historical analysis. BUT, they also start with the inviolable precondition that the Bible is the literal word of God and divinely inspired. So, forget any line of reasoning like "Maybe Paul said XYZ because of his Jewish heritage and don't forget that the Roman governor had been stamping down on ABC, so if the early Christians wanted to avoid being persecuted, they had to act this way." The correct answer is always "Because God."
Same for ISIS. They are VERY grounded in history, but they are very one dimensional. Belittling (or disregarding the validity of) their beliefs is a huge mistake, however.