Could you expand on that?
I mean that there is a competition element in social relations if the projects are on an equivalent level. e.g. OpenBSD versus everyone; Apache OpenOffice versus LibreOffice; and this competition element will help the project that's nicer to work with gain participants, and this will help select against both assholery and scapegoating. This of course requires competing projects of comparable quality in the first place, which is not so common.
http://blip.tv/tech-love-live/osb09-donnie-berkholz-assholes-are-killing-your-project-2464449
This is specifically about why it's important to get assholes out of open source projects, but it applies in general. It includes an analysis of the social cost of keeping people around who frequently make other people unhappy, and in particular a way to balance the social costs (distraction, people doing much less work or leaving, useful volunteers not joining, assholes recruiting other assholes, etc.) of assholes against the useful work some of them do.