I also think that the current market decline has a very big relationship with this hacking attack, and now the market is falling very fast!
Then you haven't done any research. That exchange wasn't even trading BTC for fiat. It's a very small altcoin exchange, that's why not many people even heard about it.
How could a small altcoin exchange with no fiat pairs cause a sell off on BTC/USD pair? The fact that it was hacked is a coincidence, nothing more.