So, Mt. Gox hack was related to BTC-e and BitMixer.io? And the common point of connection is Alexander Vinnik?

There's plenty of conjecture about Vinnik, BTC-e and Gox. Didn't know about Bitmixer.
I see nothing in the article about Bitmixer -- what are you guys talking about? Coincidentally, they mysteriously shut down just two days before BTC-e went down. I don't think they were directly related, though -- just two of the largest pieces in the darknet market puzzle at that time.
I'm surprised anyone does it with any third party mixer like the recent Binance hackers who supposedly went through Chipmixer. If I were running a mixer I'd tell them to fuck off for bringing needless trouble to me.
Association with darknet markets seems to get a lot more attention. Something also tells me that mixers aren't doing the sort of taint analysis that Chainalysis or Ciphertrace does.