Now that you've brought up both scenarios, are you actually mentally capable of linking them both together? A strong, negative reaction when someone is actively transgressing not only stops the negative action as it's happening, it offers support for the victim and makes everyone aware of what's happening. Which is exactly what should happen. It does not stop a harasser from ever wanting to commit harassment again, no one was ever suggesting that, but it does solve the here and now and dissuades that sort of behavior in general, which is important. Meanwhile, you're suggesting not doing anything (it's white knighting) and to call the authorities. As it's happening. Then you've brought up this ridiculous argument about pedophiles and punching not curing them of pedophilia, possibly after realizing how ridiculous your initial point was.