It means that they are aware that their platform was being used by the whales and pump & dump groups that just wants to manipulate the market especially the altcoins. And if they will not stop of doing these manipulation tactics, bittrex will take action on this thing.
I wonder why still trading at bittrex if trading style like traditional forex market, maybe I misunderstood, sorry
Because we used to trade on them and we can't just stop as the experience of trades there are good. But because of this manipulation notice, it will still increase their users.
The crypto is excited because of the whales and pump & dump groups, if this action stopped I can't find any reason to play altcoin again