The purpose of altruistic punishment seems to be to fight the tendency to freeload. In a group where cooperation is necessary for survival, there will always be some who coast on the effort of others. Altruistic punishment may have developed as a way to discourage that kind of freeloading. But with the advent of social media, it seems to apply to everything and everyone who fails to get in line with the group’s priorities.
The scary thing about altruistic punishment is that human beings seem wired to take pleasure in it. If you’ve ever wanted the simple answer to why there are so many unpleasant jerks online, it’s because they get a genuine rush out of being unpleasant jerks online. They are convinced they are doing something important, even noble, by punishing the tribe’s detractors.
And the truth is that it seems to work. Those who don’t fall in line are pilloried which insures others will think twice before crossing the same line in the future. Most of the examples Chait cites in his piece seem to fall into this pattern. Someone issues a word of high-minded caution to a group of women writers. Someone else makes a joke in response and then becomes the target of harassment for doing so. The person who made the joke will withdraw under the torrent of anger and be less likely to speak up again.