The weird part - and this has been borne out in conversations with anarcho-communists - is that ancap allows for ancom, but the reverse isnt' true.
Anarcho-capitalism would say "Sure, you can try your communist thing over there as long as you don't take our shit over here". But anarcho-communism would say, "Hey you over there, you can't do that - the nearby existence of that ideology threatens our ideology".

I don't know what to make of that yet, from a protocol-design lens.