BTC-e has had and might still have a very large stake in NVC, which is the primary competitor to PPC. This gives them a motive to suppress PPC through short selling.
Why would they list PPC on the exchange in the first place if they thought the way you suggest?
To give BTC-e a way to short sell it, essentially increasing the number of PPC beyond what's in the blockchain, which in turn reduces the value of all PPC.