Nobody is at fault.
A couple of ways to look at this:

1) This is capitalism at work. In an auction format, a buyer is willing to pay what the information is worth to the buyer, no more (maybe less if the purchase price is less than the buyer’s price point). Because information models are not perfect, the seller is able to capitalize on inefficient markets and make a profit. Yet the buyer does not lose because his valuation of the information is higher than $0. The seller is not at fault because he is giving the buyer something that the buyer wants at a price the buyer determines.

2) Can people help it if they are stupid?