In the past, per longstanding MIT culture, these "assholes" were tolerated and their acerbic comments usually ignored -- meaning the "asshole" would send perhaps one acerbic contribution every 6-8 weeks to an otherwise busy mailing list. (Usually the assholes did not get in dust-ups with other assholes.) More recently, though, a new generation has decided not to tolerate the "assholes" and engages them publicly with every acerbic message, leading to huge flame wars that prove very distracting (because neither the asshole nor the altruist who engages them ever likes to give up).
The organizations usually lack the will to actually expel the brilliant asshole, and it's not clear whether such a move would be in their best interests -- the asshole usually does make great contributions to the mission of the group, and I personally have learned a huge deal by engaging these people and picking their brains and sometimes recruiting them to join my projects because I know they will (and do) keep a sharp eye and tell us what we're doing wrong, and their commitment and level of effort toward a technical goal when they are on your team can be extraordinary. On the other hand, the asshole's acerbic contributions and criticism are doubtless offputting to some new members, even if not directed at them.
I am not sure whether the new state of affairs is actually an improvement. I usually think it may be better just to tolerate the assholes, and I myself have a pretty thick skin about these things. I value the diversity of opinion and perspective and technical skill that comes from having a big tent, and by picking their brains and wealth of experience, I learned a great deal from the assholes. And these flamewars, some responsibility for which falls on the people who won't tolerate assholes, prove incredibly distracting.
The people who adopt hard-line stances against tolerating assholes usually consider people like me -- (hopefully) non-assholes who nonetheless counsel caution and tolerance for the assholes -- to be terribly misguided and injurious to the long-term health of the organization. They make comments like, "I want to be in this organization with my friends, not people constantly criticizing me," which to my ears sounds possibly misguided -- you do not have to expect to be friends with everybody in an organization in order to work productively toward a shared goal. Often, the non-tolerators explain that while they themselves have thick skins, they are engaging the asshole on behalf of other, newer members who are not as willing to speak up but who are offended and repelled by the asshole.
Are we just seeing the consequences of a new breed of the pampered "Generation Y" who have been raised to value civility above diversity of experience and raw merit? Or was the old way -- where harsh emails were merely ignored, while the group proceeded with its business -- just us having our heads in the sand, and unwelcoming enough to foreclose a whole crop of talented (but less thick-skinned) people from entering and flourishing in the group? Is this period of frequent flamewars likely to persist, or are we just seeing the temporary pains of a slow revolution as friendly and civil "millennials" replace the old guard? I really am not sure.