The entire market is obviously rigged. When you can pump stocks by printing money you don't get a clear view of what's going on. The metals market are also rigged. Spoofing in future markets is an ongoing thing. When JP morgan's ass was saved when they did the wrong trade on silver back on 2012 which resulted on Blythe Masters being executed.
People are saying the same thing about Bitcoin, that banks/governments can print money and buy it, that futures are used to manipulate the price. People are talking about whales and manipulators in Bitcoin every day.
They meet in chatrooms / telegram and manipulate prices, this is no crazy conspiracy theory. Obviously this is happening in all markets to some extent including Bitcoin but with the difference being that with Bitcoin it's the only thing you can know and audit to be strictly limited in amount so any Maddof scheme attemps to disturb real price discovery are short-lived.
Everything is a [conspiracy] theory until there is evidence. Manipulation, insider trading and other illegal practices happen all the time, on any market, but it doesn't mean that the whole market is rigged, especially if the market is huge.