The US government are known for intervening in businesses that accept American users even if they're not based in the US. The darknet market Alpha Bay was shut down by the US government despite not being run by Americans. Exchanges like Coinbase which accept American users generally have more irritating verification procedures than ones that don't and they also have banned users for how they use their Bitcoin, including when they use it for activities that are only legally grey (e.g. Bitcoin gambling).
Seems like a responsible decision on Bitfinex's part. Even though they're based in Hong Kong, they're a favourite of European users who may wouldn't like the interventions of the American government interfering with their perfectly legal trading.
Would it be better to simply move out of the United States?
The user, I mean.
Depends how much money they're using and what they plan to do with it!