what you describe here, has also happened in other OSS community a while ago, GNOME and Linux in general. What used to be cool place to work with got poisoned with angry and loud trolls with no respect to developers or the fact they do it in their free time.
For example Lennart Poettering (author of pulseaudio, systemd which both upgraded Linux in many good ways) has been receiving even death threats. Horrible. Many GNOME developers left the project as well. I do not think the community got fully recovered from this yet (although it IS getting better).
Work with the people you are interested with, grow thick skin and ignore the trolls. Implement some ban system, as they feed on being replied to. I think the only way to battle this is when they get tired of the behavior (although they get replaced by new ones)and realize they are only a minority (which they are) which behavior has no effect on the project at all.