Difficulty with Foucault

In Foucault's description of panoptic institutions, he claims that by subjecting them to inspections by the public, one could effectively cut the risk of tyrannical behavior to zero. This however may be an invalid assumption. There have been numerous psychological experiments involving groups of people behaving in very inhumane ways. Indeed the whole nation of Germany was swept up in the evils of Naziism, in spite of their disciplined society. Psychological experiments such as Milgram's shock experiment and the Stanford prison experiment both reveal the willingness of an individual to commit atrocities. The studies even suggest that the individual may be more prone to tyrannical behavior in the presence of a group of other individuals. Granted social interaction is complex and often unpredictable, and for every psychological phenomenon indicating one trend, their is a theory indicating the opposite, but this fact also discredits Foucault's assumption, all be it on entirely different grounds. I don't know if I'm alone, but it seems that Foucault makes many claims in his writings which are hard to support and arguments that seem farfetched almost to the point of incoherence. Maybe it's because many of his writings (I'm not sure about the Panopticism article) are translations, but I have a hard time deciding how he is trying to get us to view a certain issue, or even what issues he is addressing at certain points.