> Zimbardo and his assistants ordered the guards to become cruel, and, moreover, that guards and prisoners alike knew what Zimbardo was trying to prove and were eager to help. [1]
I think the main problem is they weren't really "experiments" in the sense of proving anything meaningful, and serious attempts to do so did not replicate.
[1]: https://www.wired.com/story/beware-the-epiphany-industrial-c...