Look at the countries such as Norway and Sweden, where this type of liberal socialism first emerged. These nations are in a terrible state right now. They are under immigrant invasion, and Sweden is currently having the highest rape rate in the world.
I think one of liberalism's main flaw was that, to a certain extent, it assumes that people are inherently good. That given certain so and so, people would do good. It's like they forgot what the human beast is capable.
Another is that they deluded themselves that differences don't matter, which is quite flawed. Like you said, no better place to look at it than the Nordic countries that accepted these immigrants. Anyone who deny this can just look up all the videos online on how these people despise the locals feeding them.
I think you are pointing out something important.
1. Liberalism, as a child of secular rationalism and reformated christianity is inherently dependant on capability of dialogue and mutual respect. Compromise. You cant make compromise with religious fanatic and you cannot discuss about dogmatic beliefs. Liberalism is completely toothless in this regard.
2. Cultural marxism, another western cancer relativizes different value systems to bring about equality. But value systems are not inherently equal and never have been. If Islamists (aswell as christians) have inherently far more children than liberal atheists, than either by force or democracy they will eventually crash the system, that gave them voice in the first place.
You can call it natural selection.
Couldn't have said it any better sir. I read Eric Kaufmann's Shall the Religious Inherit the Earth. For someone who is used to reading non-fiction before going to bed, I wouldn't recommend you read it before sleeping. As a closet secularist, it's the stuff of nightmare for me. And mind you, this was from almost a decade ago. I just find it disturbing that secularism is not only helpless against this, a victim of its own values, but that the zealous will win regardless, by sheer rapid reproduction.