Yeah, I agree. People calling contemporary progressives "Marxists" are usually just looking for a derogatory adjective.

However there are certain similarities and the connection between Marx and CWSLL can be made -- it will be twisting and turning, and will require a fair amount of bending and averting eyes -- but it will probably pass the laugh test. I don't think that this connection is important or that pointing it out is useful, still, it's not quite the young-earth theory.