This is confirmed FUD. That was some minor exchange that traded altcoins, even without fiat pairs. Check it's position on the market and daily volume. Do you believe that somebody stealing 20 million USD worth altcoins would cause a crash of an unrelated cryptocurrency (BTC) measured in billions? If you do, you need to have your head examined.
The market depends upon these kind of news and these sort of panic will push the market down, the fact is that huge players will manipulate the situation so that the price goes down so that they will be able to short the price and get back again when the market falls, what you have said is the truth and a few million dollars worth of alt coins should not affect the market