I really think that closing his business has something to do with an outside pressure (government). As a businessman, you are making good profits then all of a sudden you are going to close your business? Yes, I agree that its no longer a joke and government are at our throats right now. And whatever steps mixing services are implementing that government will always find a way to control and put tighter regulation around it.
But what I believe is that administrators shut down the service either because they sensed they were close to becoming a target of law enforcement or because mixing volumes went down significantly after the shutdown of AlphaBay and Hansa. He is just trying to be a good guy by claiming that he is shutting Bitmixer to make Bitcoin clean. Might be he is right but I doubt a move of shutting down a successful business.
BS, they were around when Silkroad were operating and when Silkroad was busted, he still continued with his service. There
are enough people around, who value their Bitcoin anonymity that used his service. The closing of this site will not have any
impact on criminal activities, because there are still many other methods to "clean" stolen or coins acquired through illegal
means.