Vitriolic - Bitterly scathing

When time allows I read (per the internet) IOL, Perth Today and Sky News. There are some pretty good articles to be found if you do a bit of digging. One thing that strikes me as really sad is that over the three countries, represented by their news, the reader comments are the same.
95% mean and ugly. I read some really nasty ones today about Phil Collins and remembered what my mother used to say
"If you can't say something nice, don't say anything at all".
Do these comments appear because
a. the news handlers only want to publish the mean stuff
or
b. there are so many bored, lonely, disillusioned, whatever, people out there?
Today I saw a man with no legs, sitting in his wheelchair, out in the freezing wind. I bet he doesn't give a hoot about Phil Collins' talent or lack thereof.