Also they have been calling bitcoins death since about 2009 when it was created so I would not put too much faith in those predictions. If anything this sort of thing could help bitcoin, either price manipulation is identified, the culprits prosecuted and bitcoin goes on as it is. Or no manipulation (or not significant manipulation) is identified and bitcoin carries on as it is but with a govt. seal of approval (up to that point).
They could still be right, given time. They've been right for Bitcoin Gold, for example. They were right when MtGox crashed.
In one day in Nov 2017 bitcoin went up 15% in early trading then was down 21% later in the day before rebounding to close near even.
Whether bitcoin will be some like long lasting actual useful thing remains to be seen, but one thing that is undeniable is that investing in bitcoin is extremely risky.
This hold true just focusing on the general market behavior alone while ignoring all the issues such as getting money into and out of exchanges and hacks.
So this is all strange to me.