Well, you want the truth of why this is happening. Even 15, 25 or 30 years ago this was unfathomable.
Frankly it comes down to us in basically a post-Christian society. I am not one of those abortion people who get out in the streets with signs. I happen to believe the Bible is clear on abortion and life, but that is another discussion for another day. I'm not going to condemn a woman who has made that choice, but I will do my best to show her the love and forgiveness of Christ.
However, abortion has a more real (as in sight) and far more immediate consequence, even for the casual Christian or nonChristian. "Western" populations are dying. Because of things like abortion and birth control coupled with the demands of an ever-busier world, we have less kids. The average size of the family has dwindled over the past 3 decades (source: http://abcnews.go.com/GMA/Moms/story?id=1445039) although we buy bigger and better things just like this article says. We tend to have one kid (and some none) and shower him or her with more than he/she could ever need.
Our populations - America's almost included - are not be replaced at the appropriate rate. England and many other countries have already hit the negative mark. We have more medicine, more wealth, and more resources than this world has ever had available, yet our people are dying off, literally.
I would submit that this is because a failure to value life. I'm not talking about a life of nice things. I'm talking 100% about life. There are always exceptions (hey Duggars here in the US!), but the rule has been less children because they a) cost and b)take up space. We'd rather have sex with multiple partners out of wedlock and do what we want. No commitments to anything! Abortion rates have grown and grown. The use of contraceptives has spread. Because of this, we're having far fewer babies, raising fewer children, and beginning to shrink. Countries like Italy and the Ukraine have already gone well negative. In order to continue to fulfill roles and society, immigrants come in.
In direct contrast to this is the Middle Eastern and even African culture. These areas have some of the most explosive growth. They don't have the birth control and abortion rates, and they're populations are growing so much they're forced to seek better economic conditions. So, to pull my rambling post to a coherent point, they immigrate to places like England, France, the Netherlands, etc. As these waves come in, they slowly begin to overtake. We are a very segregated species. We tend to live with people like us around us. Unfortunately modern liberalism and progressive thought wants to do away with these "problems" through political correctness, education, and assimilation (basically just for the heck of it - they want it to be that way) and so we end up with the culture-over-friendliness we are starting to see.
These sheep - and that's what they are because they've been conditioned in schools and by society - are quite naive. They believe all cultures can get along. The think that we've moved beyond the savagery of past years and everyone has no progressed to something better. If we just be nice to them, then they won't kill us. Your government and certain elites (who are not with the elites that love this philosophy of liberalism) are just evil people who have only done things to hurt these cultures in the past and should feel very guilty.
Islam has a pull because it's a total system. Lifestyle, political, etc. I think folks gravitate towards absolutism by nature, because it's reassuring in a strange way. I also think it's nature doesn't encourage dissenters, so you don't hear nearly as much about converts and the less faithful.
