Also, with punishment generally, there's a problem that people almost inevitably overestimate its effectiveness. Punishment generally follows exceptionally bad behavior, exceptional behavior is, obviously, exceptional, so punishment would be expected to be followed by behavior which is not exceptionally bad just because of regression to the mean, even if punishment were totally ineffective or even mildly counter-productive. But, unfortunately, people are almost totally oblivious to regression to the mean, and so what should be the expected result regardless becomes for them evidence of the effectiveness of punishment.
Because punishment tends to immediately terminate the punished behavior, while not preventing it in the long run, punishment reinforces the punisher. The person doing the punishment is an agent under conditioning as well, but most folks fail to notice this.
Related: Son of Low Hanging Fruit
Another post on finding low hanging fruit from Gregory Cochran's and Henry Harpending's blog West Hunter.