Perhaps the Dutch are more ethical. Obama's election triggered panic buying of ammunition that resulted in bare shelves. Many vendors maintained the current price but quickly exhausted their stock. One vendors which had been known as a cheap source had stock but raised prices almost hourly. When the market normalized many remembered the vendor who used the 'whatever the market will bear' philosophy.
The extremely overpriced vendors on Amazon have an advantage. Next year they can return with a brand new name. I did note a new Amazon feature, a 'high price alert' that suggested you might search a little further. The 'price history' graph is also useful.