Would anyone accept that behaviour out on the High Street... No, i think not,
so why should it be a part of a public forum, in fact this is the only forum i know of that it seems to be acceptable, simple reason is that other forum owners need to cover their a$$ in case of litigation over content.
this may be an extreme example but shows the present day trend towards online forum/Twitter abuse
.West Yorkshire police arrested and charged Newsome under the 2003 Communications Act with having sent "by means of a public electronic communications network a message or other matter that is grossly offensive or of an indecent, obscene or menacing nature". Last week Newsome was jailed for six weeks, after pleading guilty, with the judge quoting his post back to him and saying: "I can think of little that could be more upsetting or offensive."
https://www.theguardian.com/law/2014/jun/13/jail-someone-for-being-offensive-twitter-facebook