The Belief System of modern-day liberals is founded on false premises. Some of them are: Man's equality of ability (especially in the area of intelligence), Man's equality of innate temperament, cultural relativism etc..
But the most perplexing belief is that, in their world of moral nihilism and lack of absolutes, they believe they have been somehow bestowed with moral superiority throughout entire totality of the universe and whole of time. They are morally superior to anyone that has ever existed and anyone that currently exists. Having this narcissistic mentality, and having this mentality founded on fragile eggshell-like "truths" leads them to feel threatened and paranoid at all times. They are scared of been exposed, not to the world or to their enemies, but to themselves. Deep within their minds they realize that what they believe does reflect the reality of the world. They beliefs do not reconcile with the real world. Rather than try to understand why there is a lack of agreement between the reality of their minds and the reality of the world, they chose to destroy those things that prevent the reconciliation.
It's only a matter of time before things will come crashing down for them. It's best to just remain quiet and wait, than to directly challenge them. They are like beasts in the wild. It is always your fault for provoking them.