What The Following All Have In Common:

North Korea.
Cuba.
The USSR.
China.
Vietnam.
Venezuela.
Cambodia
Countless more.
(The Berlin Wall is the outward symbol of that poison.)
Well. They have all, at one time or another, curtailed human dignity; have imprisoned non-criminals; have banned free speech; have been a signal for butchery; they have brought penury to their populations; they have employed 'thought police'; they have prevented free elections. Their own political class becomes the new elite; the new privileged class.
And yet, whenever we get a marxist/extreme socialist etc advocating yet another type of leftist enslavement disguised as 'liberty for the downtrodden' - we are assured that "It will all be different this time."
No, it won't! Same old, same old. 
So odd that capitalists can point to so very many examples of how free societies work - not outstandingly well in every case, naturally enough - but many opposed to zero is quite sufficient for me.