Some of my favourite commenters have called me a c**t (sorry about the self censoring) and a nazi. Yes, it is not always constructive and I can sort of understand those who censor commenters (even ban them). Generally I find that those who have nothing but expletives to expound soon become bored and disappear.
Jonathan Freedland however thinks this a threat to the democratic nature of the internet. He argues that anonymity allows people to say things they normally wouldn't. He is of course right, but name calling in itself is only words and as long as it is not threatening violence or libelling someone that threatens their livelihood (which is of course protected by the law of the land) then it is not so serious.
The internet is not the same as a debate in a hall, everyone can speak at once and people can edit, ignore, or read intently what they wish with ease. As long as you can type, your message can be as loud as anyone else and people can have a voice far more easily than relying on catching the eye of a chairperson.