Of course ETH is very volatile, but the problem is that it keeps following Bitcoin, even though ETH is volatile, but when Bitcoin goes down, ETH can't do anything and it goes down too.
That has been the trend, we can't change that but we can take advantage following the trend.
It's not actually ETH only, the whole altcoins are following bitcoin's movement because it has dominated the market with a big percentage of dominant rate.
To make it easy to understand, bitcoin is volatile, so when it move significantly, it will shake the whole market.