A blindness towards the realities of the USSR was common amongst the highly educated at that time. There's a reason the west had such huge problems with westerners becoming Soviet double agents, to the extent that in the UK some of the people responsible for catching Soviet spies were themselves Soviet spies. The issue was the intelligence agencies recruited exclusively from Oxbridge. The actual working classes in Britain had no time for the USSR, but graduates did.
This is still a problem! There are still a lot of academics publishing today who take Marx completely seriously and attempt to build on his ideas. You can just search journal articles for mention of him to find them:
https://journals.sagepub.com/action/doSearch?AllField=marx&S...
https://journals.sagepub.com/doi/full/10.1177/00380385211037...
This article continues the conceptual work of developing a process-oriented perspective on belonging by taking up the active engagement of affiliation (and disaffiliation) as an undertheorised yet necessary aspect of accomplishing belonging. In developing the concept we draw on Marx’s notion of work as material activity in forms of life and the sociological concepts of face-work and emotion work.