These are exactly the arguments made. The OP believes he has the right to determine what the price of a LDS should be. Barring that, any price higher is at best silliness. At worst, it is outright paranoia that the economy of the server is "under attack".
You really need to get a better grip on what constitutes market manipulation. Simply because someone has more plat than you, and is willing to spend more than you are willing to in order to acquire any given item, does not constitute market manipulation.
In a free market, the price is set by a willing seller and a willing buyer. Any item sold on the AH is by definition a free market transaction. If anything, the arbitrarily limited amount of plat that can be paid for an item sold on the AH serves as the primary constraint to a totally free market environment on the AH.
The varying prices of LDS on the various servers really only illustrates
1) the differences in the supply/demand dynamic on each server
2) the differences in the ecomomic vitality of each server
LDS are for the most part a thinly traded commodity. As such, they are subject to a wide price fluctuation. Couple that with the fact they have no meaningful production cost which would set a floor for their price, and you have a situation where just about any price agreed to by a buyer and seller can be justified.