It's an old German saying that my grandfather taught me when I was a boy while visiting him there. Rather not surprising that you've not heard it, but there it is.
Well, I've not heard that one either, so I guess we are even?
What is 'downstream' from the other? I've heard it said that:
Culture is downstream from Academia and politics is downstream from culture. So:
Academia => Culture => Politics
Rather disconcerting as we are now seeing Marxists marching on the streets, pushing their 'Marxist culture' into politics, and we appear to have been seeing a resurgence of Marxism in higher education for quite some time now.
++ I don't understand your use of Marxist. One can express concern about our skewed distribution of wealth and power, probably the worst in the developed world, without believing in inevitable class struggle. I was taught about Marx while in a Catholic seminary. He was a brilliant philosopher who got a lot right - workers of the world did unite and lose most of their chains - and a lot wrong, that this would lead to dictatorship of the proletariat. He wrote at a time when conditions for workers were slave-like, indeed the South countered criticism of slavery by pointing to conditions in US factories. And what is "Marxist culture"?