Pikhristos Aftonf:
In addition to what you wrote, a lot of Europeans and Americans don't speak Arabic, so they don't know any better and sometimes assume that the bad things the Middle Eastern Christians tell them about Islam are sour grapes or just blind sectarianism or whatever.
Islam knows how to manipulate things to get good PR for itself, and lots of westerners (I feel like this is particularly true of Americans, but maybe others too) like to root for the "underdog", so when their Muslim "friends" talk about the nakba or Sabra and Shatila or whatever, the Westerners think "Oh, poor Muslims! They are so oppressed!" Their Muslim friends don't tell them about the robberies, forced taxes and other intimidation that the Christian communities around Tel al Zaatar were subjected to before that which led to so much tension and calls for the camp to be closed, and much less about the Damour massacre in 1976 that killed 684 civilians at the hands of the PLO and the LNM. Damour was a Christian town, so of course it never comes up...
So, yes...ignorance and manipulation of the sympathies of the well-meaning but naive westerners. Nobody listens to the Middle Eastern Christians, nobody in the West defends their own values or religion, and so Islam continues to grow unabated. Lord have mercy...