I have no idea why Ethereum was dumped harder than most other altcoins.
Generally speaking, bitcoin and ethereum are the most stable coins.
the ethereum effect is thrown harder resulting in the price of ethereum now decreasing drastically, now the ethereum is in a low position but in the future ethereum will still continue to be one potentially coin despite rising slowly.
There are rumors that eos team is dumping/will dump their eth colected durring ico stage(more then 1 mill)on main net launch so they could kill their main competition with that move.Why it was on bitfinex its because bitfinex team wants to be one of those companies who will on eos team list