I've just read this on a popular UK forum and thought it rather apt...

Trust me, nobody should post on any forum, anywhere unless they have hide like a rhino and are wearing asbestos knickers. If you think [website name] is bad you should check out some of the online gaming and wrestling forums out there where some of the worst offenders are the under 16s

Honestly, if someone's being nasty it's best not to bother with them if it's upsetting you. Just add them to your ignore list and it's easy to forget they exist. If they're cretins you don't need to read their posts anyway.
Never a truer word spoken about the perils of internet forums.