Our species spent 99% of our time as hunter-gatherers, usually in groups of around 150 people. Ostracism was an effective punishment in those days. We may have internalized that, and so instinctively see "Kick them out of society!!!" as a solution. 1)

I have no idea how this works in the information age. There's a weird clash of our instinctual behavior with the extremely powerful new tools in this very new environment. 2)