We place a lot of trust in medical professionals. Your doctor gives you a prescription for something - for most people, you take it on the assumption they know what they're doing. (Yes, I realize there's likely a sub-contingent of the HN crowd that Googles everything they take -- but there was no Google back then, and particularly not in East Germany, where almost all of the information you got was carefully controlled). Witness how easy it was for Larry Nassar to perpetuate years of abuse against over 250 children, and that's today in the US.
Even if the trust was simply "hey, this will help you perform better and it's safe", and the "it's safe" part is a lie, it's still abuse. And the things described in the article are actually far worse than just that.