I agree, but my point was slightly different. There are legimate points to be made -- if not agreed with -- concerning the benefits of immutability, of single-o

I agree, but my point was slightly different. There are legimate points to be made -- if not agreed with -- concerning the benefits of immutability, of single-ownership patterns, of equational reasoning, etc. which are central to the modern FP ethos. You can make OOP and FP appear equally useful by framing the discussion with the expression problem, but I think that framing is myopic, and flattens a lot of the actually interesting distinctions and philosophical differences between the two.