I don't think poloniex caused the market to crash because the issue on the website (DDOS, hacking and other problem)
always be found on the internet include on poloniex, i don't think there is related between the price with poloniex down
because there are not the coins disappear and right now poloniex is fine.
They did kind of crash the market, their site is the largest altcoin exchange available, if they go down, everyone will panick, and try to sell their positions, which is what happend here.
It's ofcourse bad that this kind of stuff still happens in 2017, but that doesn't mean that there is no money to be made.
As sad as it is, you could've picked up a lot of coins for a cheaper price at the time poloniex was lagging like crazy.
It is like blame the poloniex because the website was down, even the poloniex doesn't sell all of the coins
the traders are panic selling and make the price went down right now
we blamed poloniex even they never sell the coins of costumers and there are not the coins was disappear
from there, the market to crash because of the traders panic selling.