From what I can tell, the issue is twofold: Informed consent, of which there was very little, but that's not exactly rare until recently, and running the trials on "marginal cases" - hemophilia comes in differing severity, and given the risks of using known contaminated factor VIII using it unless necessary probably wasn't the best idea.
But, you know, that should have happened before they were approved as products.
I'm horrified and don't know what the hell to say. Humans have a long history of gruesome medical experimentation and I'm just not in a good space for addressing this well.
If correct, these satanists might argue those were of good intention.
Informed consent was broken, so I guess it's a lower hanging fruit for bringing justice. That said, I don't know if informed consent had been established by 70-80s.
You really need to bone up on the acts of Christians, if you think only satanists would irreparably harm others, including children.
If it was known that those products had a high chance to be contaminated, no amount of consent would make any of this ethical. The only ethical way to use them would be if there was no alternative available and the potential infection with Hepatitis C or other viruses would be less dangerous than no treatment at all.
Consent is a necessary requirement for an ethical clinical trial. But it is not sufficient by far, the risks and benefit of the trial need to be proportionate for the patients.