Over the years, I have noticed that every time Bitcoin's price goes down other alt coins follow suite. And When the price of bitcoin increases, its expected that altcoins go up in price shortly after. Presently as bitcoin price reduced other altcoin prices was affected too. Fact is that Bitcoin has the most secured network and it was the first among others. No doubt some alt coins was made of bitcoins clone.
It is primarily because of the traders rather than the hodlers.
They group all cryptocurrencies in one category, thus when one big cryptocurrency makes very high gains (e.g. BTC), they buy up the other big cryptocurrencies, and it has a kind of knock-on effect on the market.
That type of thing happens in all of the cryptos and all of the markets. If there is a good case to be made about the current situation we are in, that's what we are doing right now with the investments we do together just like the hedge funds does it in the stock market.
I get that it may not be something some people like and could call it a manipulation but at the end of the day we couldn't be really saying it's a bad thing considering how it has been a situation in the stock market before as well and why we wouldn't be really caring about it there, so we shouldn't care about it here neither. This is of course my personal opinion, maybe I am wrong but it feels like that would be the greatest idea to do right now, to let it go.