Invalid Premise #1 is "full BTC refund means the EXACT NUMBER of BTC paid NO MATTER WHAT"

This was debunked months ago.  It was a ridiculous, impossible interpretation constructed to benefit the cupidity of its proponents.  There are many highly imaginative subplots to this conspiracy theory involving hedges, reinsurance, and secret escrow accounts, none of which were ever mentioned by HF or their TOS.