Obviously, Gmaxwell feels he wasn't properly acknowledged for his coinmixing work
I haven't done any "coinmixing work" if you're talking about CoinJoin, darkcoin threw around my name quite liberally initially until people warned them not to. I don't want my name anywhere near this thing.
It is CoinJoin but using a server chosen at random.
Maybe it is how would you know? ... in any case, randomly selecting a
server is distributed but not decenteralized. The "random" servers are well positioned to track every user using them. A well implemented coinjoin would combine users with multiple other users in a way that _no one_ knows what the input/output correspondence is beyond each user knowing his own inputs and outputs.