You make it sound like the customers money belonged to HF before they shipped the product. I disagree.
You make it sound like HF wasn't clear their advanced 28nm ASIC was not an off-the-shelf mass produced commodity device like a Hello Kitty toaster from Amazon, and only available in the future via pre-orders.
Customers' money was clearly being spent to fund the development and manufacture of their machines; it belongs to those who provided components and labor.
Do you really think our BTC were being held in some secret escrow account, perhaps guarded by enchanted fairies, and that HF was footing the entire bill to charitably provide us with ASICs entirely at their own expense?
Why would HF bother to use BitPay and give them a % if our BTC were going into escrow?
In no plausible scenario is your desired windfall a reasonable expectation or demand.
OTOH, if BTC went to $1 and HF tried to pay out $51 refunds, they would have gone to jail or at least gotten in trouble.
The only legal course of action was for HF refund the purchase price (which as always denominated in USD) in fiat.
It would be no different if you wanted a refund for an exact number of Euros or Yen.
HF is simply not liable for fluctuations in media of exchange provided as a convenience. That's not how it works. Ask any lawyer.
This has already been explained several times; you and Skye are unbelievably slow learners.