Back in August, the editor-in-chief of Communications of the ACM wrote an editorial in which he wrote, "It is regrettable, I believe, that the open access (OA) movement found itself in the IP communist camp."
Before you dismiss this as out of touch, please go and read the comments on Mark Guzdial's post about the editorial, particularly this one, in which he points out that most of the SIGCSE community (i.e., most people studying computer science education) don't have research funding, and hence are reliant on the money raised by the ACM's paywall to support their activities. But please then also read Cameron Neylon's comments starting here. As he points out, the ACM and IEEE's high-priced duopoly, which is essentially immune to market forces, looks a lot more like communism than open access does.
There's another way in which the ACM and IEEE remind me of my brief first-hand experience with communism. In the absence of frequent, brutal crackdowns, every command-and-control economy produces a gray market — a place where people can do business as if they were living in a free-market society. Officialdom may turn a blind eye to it, or even sanction it under names like "special economic zone", but it has to exist, because otherwise people would starve.
Pre-prints play that role in academia. One by one, journals and professional societies have gone from "thou shalt not" to pretending they don't exist to "OK, go ahead, but we're still putting the real paper behind a paywall". The end result is things like this conference, where unofficial copies of roughly half the papers are available through the conference's web site. That gray market is, for me, a sign that it's the professional society's model that should be under scrutiny.
I accept Mark's argument. I accept that insisting on free access to all scientific publications without providing some other way for the communities that produce them to raise money would be a disaster. But that's not what OA's supporters are advocating, and calling us "communists" is neither accurate nor helpful.