I'm inclined to agree with this take and, although I can't speak for the tech-using Mennonites and their level of non-theism, I can say that they are very often at the forefront of social justice movements and also in Ukraine during the civil war, a proportion of the Mennonite community there took up arms and joined the Bolsheviks which speaks to their compatibility with communism (although these were Mennonites as defined by an ethno-religious group and not necessarily strictly devout as per the Mennonite faith - details are extremely scanty, unfortunately, and you'd probably need to speak to an American Mennonite historian to find out if there's any more information about the Bolshevik Mennonites) so I would find it convincing if someone threw the progressive Mennonites into this group although personally it wouldn't be my first answer.