they gone scam
Nope, they are not scamming people. The problem is for those who cant verify themselves. Bittrex have to protect themselves too from being used by money launderers and they have to comply with the local regulations. It's a legit business and its about money, so they have to be strict with the people they are dealing with.
Yet Poloniex will let unverified users withdraw up to $2,000 worth of crypto per day, and they are also in the US.
The Bittrex claim is BS, they are just trying to lock up funds.