The higher the salinity, the more stress on the fish's biology. Hypo performs more than eliminating the parasite, it makes survival easier on the fish. It has to work less to clear out the excess salt from it's system and it increases it's appetite. All this was clearly noted in those links. If you don't do your homework, you fail the test. In this case, "the test" is the fish's health or basic survival.
Read up on the care and treatment of marine fish before buying more, Sorry for your loss.