The vast majority of people never interact with the system to get any kind of response for it, also, most of the feedback is going to be negative, there has never been a punishment system in history that has been seen as a positive across the board.
Most people who are content aren't going to voice they are because that just doesn't happen, people don't go around stating arbitrary things like that, it is like how people in real life don't randomly pop into police stations and say "Hey, you guys are doing well, keep it up." same concept here.
Another point is that people only knows systems when they don't work for them in a timely fashion. It is like how you never hear about the times cops do their jobs overtly effectively to the point crime is obscenely low, but you will always hear about the time they weren't there to do something. Ever report someone knowing they deserve a punishment and you don't get the message saying they were punished, you assume it is the system just not working.
So, all you are going to get are the people who get punished by it, and thus, you won't hear any real criticism or anything constructive or positive about said system.