Liberalism's ersatz religion rings hollow for lots of people, whether they're consciously aware of it or not. We now see people looking to exotic faiths to fill that void.
In other circumstances they might have looked to the West's native faith -- Christianity -- but the same liberal elites have spent decades continuously maligning and disparaging it. They've been assisted in this to a large degree by modern Christianity itself, which in an effort to answer liberalism's accusations have churned out a syncretic, milquetoast version of Christianity. In contrast to this waffling reluctance to speak boldly, they see Islam which speaks with categorical certitude.
I guess what I'm getting at is that the modern West is producing a lot of collateral damage in the form of these wandering souls, and for these wandering souls a bold, self-confident barbarism is more attractive than a weak, self-doubting goodliness. The Christian churches, whether Catholic, Protestant, or Orthodox, are failing the flock with their timidity.