Manipulation is all relative and is something that largely only happens between people's ears. Bitcoin isn't being manipulated down, it's just the speculative nature of this market doing it.
I think so too. Another factor to take into consideration is that a large part of the support on the buy side gets withdrawn when charts indicate a downtrend. If one or more large accounts try to liquidate their holdings, they have no choice but to take a hit and accept that slippage can't be avoided when using spot exchanges.
In that regard, it's a good thing that more exchanges start to dig into OTC trading. Instead of large accounts dumping the spot market down, they can get matched to an off-exchange buyer and settle the transaction there. The fee the exchange takes is well below that what large accounts would lose anyway due to the crazy slippage.