I believe there are numerous problems with respect to the human rights situation in Iran, but one of the problems that exist over time when any authoritarian regime is allowed to commit human rights abuses in a widespread and systematic way over an extended period of time is that the people involved in those abuses, when there is no accountability for those actions, come to believe that they are above any law and are capable of committing those crimes in an ongoing way without fear of any retribution.
What starts as people perhaps following orders to commit human rights abuses becomes their feeling that they don't even need an order to commit the abuse because people will look the other way. When people who commit crimes in the name of the Islamic Republic are not arrested or investigated or prosecuted, then you also see a climate of fear taking place among the populace and a recognition that it's very difficult.