I believe his point is that he doesn't like working with software where that software's community is populated by assholes.

Perhaps you don't mind. Perhaps you're immune to the hostility and aggression of others. For many of us, it doesn't, and it makes working on or with the project unpleasant.

Life's too short to be spent at a shitty job. I see working in a hostile community as the open source version of a shitty job.