it seems like u.s wants to control cryptocurrency and make it their own and bully other countries cause they are scared it will take over the u.s dollar. bitfinex is doing the rite thing taking u.s residents out of the equation cause the baggage is the u.s government.
I think the feds are just picking the low-hanging fruit. They realize that cryptocurrency is here to stay. Bitfinex still faces problems, because they operated in the US for years without a license. And then, there was the whole token thing, which may not sit well with the SEC...
what about Kraken and Poloniex? they are based in USA and they operate without license. they are in the same position as many other closed exchangers due to the operating an illegal money transmiter