Well I am, but I left the argument to those who had some familiarity w/marx.
I think you demolished most of CB's arguments except the first one, which goes to "to each according to need."
How would one distinguish among persons in respect of "need," putting aside obvious differences due to a physical impairment, old age, infancy, etc.
You got two able-bodied blokes of working age, different abilities but that's not a matter of need. What is the basis for saying one needs more than another? If there is none, equality becomes the rule of thumb, no?
Suppose I have an expensive hobby -- jumping out of airplanes, and someone else is into tiddly winks. Under communism, are both hobbies indulged on the basis of 'need'? I doubt it. The expensive stuff is rationed and made accessible in some kind of fair manner. By lottery, first-come/first-served, whatever. Some way of not discriminating among claimants to the good. Equality.
mbs