If you have any issue with Bittrex and Poloniex address it but calling names and alleging such criminal label is not good. Have been this 2 exchanges for over 3 years and have no issue with, though the exchanges might struggling with some internal problems it does not affect the users of their exchange. Bittre and Poloniex are exchanges that barely list coins and do a lot of research on their coin, they are the only exchange they stop an IEO late on their exchange because of scam discovery
Bittrex is scam. I've lost money there myself due to their fucked up KYC system. If someone has been using them without issues it doesn't mean they're not stealing from other users because they are. And they are quite clever about it, $20 here, $50 there - not enough to take them even to a small claims court. Even if you could sue their Nevada shell corp you'd probably have very little chance to collect on that judgement.
I have filed complaints with CFPB and FBI/IC3 and I would suggest everyone who lost money do that (also check with FTC, SEC, and local regulators depending on circumstances). Each individual complaint doesn't matter much but if it reaches a critical mass hopefully it will cause them some trouble.