Or, for example, the most-upvoted post in LW's history.
It's been deleted now AFAIK, but this post was dismissed as an outlier due to Karnofsky's relative celebrity. Establishing an historical trend (which does exist, as far as I recall) would be more useful evidence.
E.g. check out the anonymous multifoliaterose's numerous positive balance SI and specifically EY-critical posts, some of them rather harsh indeed in content, although mostly following usual conversational and politeness norms (with some striking exceptions):
http://lesswrong.com/lw/2l8/existential_risk_and_public_relations/ http://lesswrong.com/lw/2lh/other_existential_risks/ http://lesswrong.com/lw/2lr/the_importance_of_selfdoubt/ http://lesswrong.com/lw/2m5/transparency_and_accountability/ http://lesswrong.com/lw/3aa/friendly_ai_research_and_taskification...
If it's worth saying, but not worth its own post, even in Discussion, it goes here.