you need to make a difference between
-the anonymity of the node which is not desirable and not possible
-the anonymity of the human who operates the node which is desirable
Discussion
nodes are meaningless. centralization and state attacks is a danger that can be observed in a proof of work network because it's very difficult to create and install nanometer scale asics without someone knowing that you did it.
without that there would be no way to know if all the miners are secretly owned by one person