Since you obviously missed the point, I'll repeat and make it even clearer:
- What you call extremism isn't really seen as extremism in those Islamic cultures
Unlike in Western culture. Where appeals like killing gays, and other deplorable stuff, are greatly looked down upon.
- Which also implies that Christian terrorism in the West, or even in general, doesn't have the amount of passive and active support that Muslim "extremism" has
Congratulations on finding a lunatic pastor claiming his interpretation of sinful behaviour in the Bible is the correct one. How many people actually started killing gays because of what he said though? Now, compare that to the number of LGBT crimes in Islamic culture. For the sake of completeness, compare the number of Imams calling for violence against the LGBT community with the number of Christian pastors doing the same.
However, the biggest difference between a Christian and Islamic preacher representing their faith is the little part of history where the Renaissance happened. Since the Renaissance, Christianity became largely entwined with philosophical humanism - basically making Christians value (non-religiously based) universal rights over blindly following a holy book. The same point cannot be made for Islam, which hasn't seen such an historical event. There's
only one interpretation of the Quran, else you're not a true Muslim.
This major detail is enough for the (at first sight hypocritical) statement: One cannot blame the entirety of Christianity for individual actions; yet it is possible to do that for Islam.
Let Islam go through a Renaissance-like period first, essentially modernizing it, before you compare "Christian" terror with Islamic terror - or even more strict: Before you compare behaviour of Christians with behaviour of Muslims.