I'll clear all the FUD : Ethereum wasn't hacked at all. That was just The DAO. There is not consequence on Ethereum at all.
Then, to reply to OP, that's quite simple : the halving. That's what's draining all the altcoins for more than a month.
In markets, perception matters more than reality. ETH is perceived as vulnerable and uncertain, and confidence is low, so people sell and the price trends down.