Kraken and Poloniex are registered in USA. Even they will ditch the US customers, it means nothing because they are doing business from USA without being MSB.
Yep. And regardless of what they do now (like registering and moving operations to another jurisdiction), it can't erase the past several years of operation in the US, and serving US customers. It sucks to be a US resident right now if you haven't been paying your taxes (can't send those coins to regulated exchanges). Also sucks to be Kraken, Bitfinex, Poloniex, Bittrex..... but especially the former two, because they've been processing fiat withdrawals as well for years.
Polinex and Bittrex don't do fiat.
Bitfinex is tightening requirements for US customers, maybe first signs of a pull out from the US.
It doesn't necessarily matter if Poloniex and Bittrex don't do fiat processing. (In fact, Poloniex says up front that it is an MSB, registered with FINCEN, but it doesn't have state licenses)
I believe that provisions of the Patriot Act or legislation/administrative regs that came after expanded the definition of MSB beyond simple fiat currency processing to value transfer. The BTC-e indictment also refers to the platform being used as a means for US customers to transfer money to one another. We don't know if that means BTC-e codes or cryptocurrency or what, but since fiat processing required verification by the intermediary, it kind of sounds like they are referring to the former two.