Just how are they being manipulated. Its a bidding process. You can tell the world what they can bid on future oil supplies?
Go read the Feds numberous reports on the energy futures markets, they can be manipulated quite easily, and numberous studies by the fed have come to that conclusion and recommended better enforcment and regulation of them... but even though they know they are succeptable to corruption and manipulation they have done nothing to secure them.
Back in 2000/2001 several studies came out all state the same conclusions... yet none of their recommendations to resolve it have been enacted. Energy futures trading is a scam... The Stock market is a "bidding" process too, but that didn't stop folks from bribing other folks in 99 offering them stock that was currently trading for $600 a share, for $35 a share on the days of IPO's...
If you think the energy futures markets in the US are beyond reproach, you are grossly misinformed.