Yeah I think manipulation is the wrong word to use here.

Market manipulation has more to do with what a person says on the boards or chat than it does with what they do with their coins.

Anyone who lies about their position, or encourages others to buy/sell deceitfully (e.g. It's the end of bitcoins!!! They're going to the moon!!) with the intention of misleading others into panic buying/selling for personal gain, is a manipulator.

Someone putting up a bidwall (either way) is, by action, an actor, and not a manipulator in the market. Even false walls can be bought out before they can be removed.

Someone sweeping the market left and right with massive buys or sells is no more a manipulator than anyone else with real money or coins on the market. They just have a hell of a lot more than others.

The truth is that when a person is speculating, they're only competing with other speculators for the same money/coin, so I don't know why anyone should think it was fair. This is what the free-ish market is all about...and probably why it's so regulated.