It can only be good if many people are waiting down there to pick up the dip, other than that I don't belive they can crash market that much as they honestly don't hold any large amount that could tank the price like 40% or so.
This cannot be true as EOS team never came out themselves to say this and apparently, anyone could have just come up to make this up. Even if this is the case and ETH gets dumped, then we will pick the low value like you said, but the ETH market is a huge one on its own, and I do not see how EOS whatever, as claimed by the OP will have any effect that much on ETH or create that sort of perception for investors. Also, it is not like EOS itself is doing that pretty good in price lately.
As a trader, I care less about this as EOS cannot at the moment out-compete the Ethereum blockchain. Both can co-exist in my honest opinion and without trying to undo the other.
Always competitions are going everywhere but we do notice it only drastic changes are occurring. Situations may change and we traders do forget when ethereum gets better prices. It happened in past so why not in coming days.