"Debase the morals of the people and they will have no courage to resist."
Well, it was one Vladimir Ilyich Lenin. The upper class left loved this kind of thing, of course, as it justified the licence they sought for engaging in hedonistic behaviour and depravities of all types.
The rather less mighty leftwingers with a burning commitment to overthrow of the capitalist system sat back and watched the seeds of destruction begin to burst forth, blossom and spread its roots deep downwards into the middle classes - ironically, where its main power base would emerge. In so many ways, the working class element of marxism is the least important bit in its implementation.
Lenin was a great many things but fool he was not! The above quote is the key to understanding the tactics which have been employed against western society starting as early as the 1920s.
It is a major plank of working against faith too. Remember that Marx himself described 'Religion as the opiate of the people.' Communism knew from the outset that it had to set its face irrevocably against the Christian Church and all the good that it represented.
Christians who espouse leftwing causes should really look at the roots of where they are misplacing their political beliefs.
'Christian socialism' is an oxymoron.