"If we added a feature that would enable players to search for a specific item type, it would make the high demand items sell incredibly fast. This would then result in the high demanding items completely disappearing from the market, and almost no one would find the type of items that they need."
So, to prevent almost no one from being able to find what they need, you make it so no one can find what they need? 😉
Someone tell EA that an efficient and effective market is one that clears itself readily, not one that hampers user functionality for the sake of keeping the store shelves prettily stocked.