Normally it is not bad for Altcoins if BTC drop. BTC drop mean people are try to invest in altcoins but nowadays most of the investor are afraid of the market thus they will stop buying altcoins although the BTC is dropping.
Yes you are right because people's thought is if BTC rises then altcoins too will rock if BTC drops then altcoin too will drop the value. As most of the people's have scared after the market is very bad now. People have different intentions, but look at ripple effect last month. People need to trust on this everyone has a turn wait for it.