"Let's just take violent revenge upon a few individual rapists,"

Intriguing interpretation.

It's not violent. There is no violence implied but that of the rapist.

I don't think 'revenge' is the motivation for the creation of the device. It physically prevents *full* sexual assault by being a physical barrier which causes pain upon attempted forced penetration. Much like barbed wire or having a guard dog does with a burglar. So there's no after the fact 'revenge'.

A third of the male population of SA does not constitute "a few individual rapists", it constitutes an extremely high percentage of the population, ie a third.