I think I have said this before, but if there is no outside, there is no inside, and if there is no inside, there is no culture, at least no common culture, which is how most of us tend to use the term.
I will speculate that Leftism–and cultism in general–is an effort to turn Gesellschaft into Gemeinschaft through direct emotional, social, political and eventually physical violence. This was the core argument Rousseau made, and upon the basis of which events as varied as the French Revolution and Pol Pot’s political democide were perpetrated.
But a true culture frees people, at least from anomie. Confining people into small boxes is the opposite of the intended result, which can only be obtained through sustained freedom protected by the rule of law, and enriched through a shared base moral code.