Okay, so people get nervous about Bittrex delisting those useless shitcoin? You always see or read, what you want to. If the SEC would want all ICOs delisted from any exchange, they would have done so already.
Not saying it wont hit some ICOs, especially those with bad intentions or those letting US citizens in. But most didnt accepted them, because they didnt wanted to get in trouble.
Keep calm and speculate with tokens, not information.