This is the latest and, the only, statement I can find from Bittrex:

https://support.bittrex.com/hc/en-us/articles/115002187632-Statement-on-disabled-accounts

"Statement on disabled accounts:

Ryan
Today at 12:28

We would like to address recent reports regarding Bittrex account suspensions.

We occasionally conduct compliance reviews and are working vigilantly to protect our service and our users from harm. As part of a compliance review, we have temporarily suspended certain accounts pending the completion of the review. The total number of suspended, closed, or banned accounts is very limited: less than 0.1% of the total accounts on Bittrex.  More than 99.9% of Bittrex accounts are unaffected.

Any reports that Bittrex miscalculated or misapplied its exchange fees, that there is a security problem with the exchange, that Bittrex lost any coins stored on users’ behalf, or that Bittrex is banning people trying to access Slack to discuss the status of their accounts are incorrect.  We are committed to making Bittrex a strong, safe, and compliant exchange where people can securely participate in the digital currency economy.  We ask for patience from our highly valued customers.  As for us, we plan to “keep calm, and carry on.”

So that's it huh? That's the explanation? Not enough, not at all. They could have avoided all this grief and nonsense by simply alerting us first or, at the very least, putting up a banner on the home page. Does no one consider the consequences of their actions any more? What if someone, on the edge, thought they had lost all their money and jumped out a window? This is no way to conduct business in this day and age. They should take a long hard look at themselves and make some changes in favor of the customers not the convenience of Bittrex. Communications and trust are needed for success. I see neither here.