The drop has got to do nothing with the exchangers or their act on the altcoins in negative way. The story of this is everywhere on the forum and if you read carefully then you will come to know that what happened currently is gox a guy with more than billion bitcoins sold his most of the coins and thus dumping the prices of the bitcoin. The altcoins dropped because of the indirect effect of the bitcoins drop as people tend to get panic reactions and thus selling the altcoins as they are scared currently. This is normal I believe and there is contribution of any exchanger into this so don't mix up things here. Just know the true news from the forum itself.