I would argue that 4chan develops a reputation as a community-as-a-whole, and pro-social (if you can call it that) behavior is encouraged (in some ways) because of the "good of the community".
People on 4chan are jerks if viewed from an outsider. But 4chan regulars probably think nothing of it
The author is specifically talking about places where you go to interact with people who share your interests and _aren't_ jerks.