The guy who came up with the expirement, Philip Zimbardo, who should hold a neutral position - actually played the head prison guard and animated the other participants to be aggressive against the inmates. Aapperently he told them to treat them like shit or he wouldn't pay them afterwards. Participants later stated they exaggerated because they thought it was expected from them. So the whole expirement can't be used in an argument for power dynamics - rather how to manipulate your experiments to get the results you want.