I agree subreddits and IRC, can be moderated by users who don't need to directly have repo access, sort of an abstraction, unlike how github repo members/collaborators would, can be a huge assist to eliminating that toxicity. It even has the potential to be handled before the negativity ever gets to those who have so much going for the project, unlike github issues currently which really require the collaborators who have usually contributed a lot to the project, to directly mitigate the toxicity there. I think it would be a great asset if github added the ability to give certain collaborators access to issues only which might aid in fixing this issue allowing there to be sort of moderators/support users who love the project but maybe are better at giving back by moderating issues more than contributing code.