Most Westernized people are quite familiar with Christianity and to a lesser extent, Judaism, whereas they really wouldn't understand most arguments about the theological underpinnings of Islammunism. Besides, most of the target audience of such a book is already aware of the damage that Islam causes in this world, and clearly sees how it leads people to do irrational things, like slay others for the sake of hedonistic pleasure in a next world.
Perhaps there is much less moral equivalence between the way Christianity is practiced today with the way Islam controls the minds of its adherents, but several centuries ago, you'd have a tougher case to make. Go to Wikipedia, and look up "torture", you'll find a history of devices utilized by both Catholics and Protestants alike to deal with the other when their group had the upper hand. The only really positive thing to come out of it were groups of people who fled Europe to seek religious tolerance in the New World. One of the truly great developments of our Founding Fathers was the idea that people did not need to be imprisoned, impoverished, tortured or killed for having a different interpretation of an ancient book.
All religions involve belief in things that are not verifiable, and require a suspension of disbelief (a/k/a faith) to operate. Yes, some atheists work really, really hard at trying to convince people that there is no deity, but the majority of us simply don't believe in something that most believe in only because our culture has conditioned us to believe in it. We just don't make the connection between the pretty flower or the stars in the sky, and some power-grabbing religious leader dictating what we may consume or how we may seek recreation.
Can you show me where in the Bible Yeshua (Jesus) commanded the persecution and torture of heretics? I can show you in the Quran where Mohammed did--and that is why playing the moral equivalence game is a demonstration of ignorance.
If Christians (or theists) are such only because of their culture, what makes you special? Aren't you just an atheist because your particular upbringing and cultural milieu brought you to where you are? If we are only products of our environment, then we are all products of our environment.
Go to Wikipedia, and look up "torture", you'll find a history of devices utilized by both Catholics and Protestants alike to deal with the other when their group had the upper hand.
Go to Wikipedia and look up Stalin or Mao. Non-starter.
some power-grabbing religious leader dictating what we may consume or how we may seek recreation.
God doesn't dictate what you may consume or how you may seek pleasure. He just dictates which are right and which are wrong. You are free to consume and seek recreational pleasure at your leisure.