I disagree. The blunt people (who come off as "dicks" to the outsiders) are like a community's immune system. They protect the community against the sort of people who take accurate engaged criticism, make one or two changes to fix specific issues, and then resubmit their work, wasting the community's time and resources, driving off the people who are making good-faith efforts to help the community. They're not being dicks "just for fun". They're protecting the time and attention of other community members by saying bluntly what many other people are often thinking.

Communities that have too many of these people become closed and ossified. Communities that have none of these people evaporate, as the core contributors just walk away and find better things to do than deal with people who are more interested in getting fame and attention for themselves than making good-faith efforts to advance the project of the community. The trick is to find a good balance.