This would all be corrected if the exchanges charged money for cancelled orders. These traders are placing orders on a massive basis at prices they never intended to honor in order to get the exhanges to transmit these fake prices and trick others into action. (Often cancelling 100x the orders they transact). This is called "price-fraud", "spamming", and "market manipulation" in other parts of the economy.
Exchanges should charge a transaction for orders when they are placed... Not solely if they are executed. It is actually a fairer system since exchanges have to bear the cost of transmitting prices, volume, book depth, etc. on order placement... It could actually drive transaction fees down for those who cancel infrequently too (people trading for true commercial purposes) since the exhanges could average down thr cost of their transactions with mass-cancelers and they can trade with better information.
Oh, and unloading or buying large blocks of stock SHOULD move the market... by definition. Allowing people to mask that is a manipulation as well.