“The demo last Saturday was irrefutable proof that the concrete situation...”

From the NYTimes, article by Doris Lessing pointing out that such phrases (which are written in a language that seemed designed to fill up as much space as possible without actually saying anything) comes from Communist jargon - just like the phrase "concrete steps".

Words confined to the left as corralled animals had passed into general use and, with them, ideas.

Funny thing is, you do see people writing like that - especially people who are trying to impress. I remember reading KeY's social work academic texts and thinking that the writing was awfully bombastic. And you sometimes see it in civil service writing too. Never associated it with communism though. Got to find someone from that era and ask...