Then perhaps piracy is an indicator that the pricing is considered too high, above the threshold at which a potential customer decides to either not buy it or pirate it.
The question then is how the ability to pirate affects that "reasonable price" threshold, amongst other hard to quantify effects of piracy.
If we assume that the researchers in question are in fact intentionally misleading and misrepresenting the facts then yes, that is alarming.
But what does that have to do with being American? Pocketing money from industry at the expense of public health and safety would be disappointing given any nationality.
Due to the higher friction of trading items in Diablo 2 as compared to that of D3 (auction house) there's an assumption that the drop rate of quality items in Diablo 2 was higher than in D3. Further, in D3 the items are a lot more liquid due to the ease of exchanging on the auction house and so there's a feeling of instead focusing solely on collecting gold and then choosing an item on the auction house rather than enjoying "slot machine" mechanics.
The question then is how the ability to pirate affects that "reasonable price" threshold, amongst other hard to quantify effects of piracy.