Fanatics end by subverting their own argument. For instance, animal rights activists have some point, and many people feel sympathy with them. But animal rights fanatics do not have a point. They are the sort of people who threaten human beings in their effort to 'defend' animals.

A fanatic commits to an ideal to whatever end. A fanatic throws everything aside to pursue their idea. Take something which it would be good to be committed to, like basic human rights. You might campaign for such a thing. You might spend every day of your life pursuing such a thing. But once you become fanatical about it, anything can happen.

For historic reasons - principally the political Right's opposition to gay rights - most gay spokespeople continue to think that the political Right is the sole locale from which anti-gay sentiment can come.

Rather than being a 'perversion' of Islam, it is truer to say that the version of Islam espoused by ISIS, while undoubtedly the worst possible interpretation of Islam, and for Muslims and non-Muslims everywhere obviously the most destructive version of Islam, is nevertheless a plausible interpretation of Islam.