On line things are different. While there are sites where like-minded people can pat each other on the back and support their points of view, there are plenty of sites that at least try and address topics where multiple views may be help. Technology news is a classic.
The internet has long been a safe haven for trolls who love to wind others up or simply don't have the social skills to see what they are doing. However we seem to me moving into a time where opinion has become a matter of faith. Faith, as we all know, is not based on fact. Faith is usually undermined by fact and destroyed by reasoned debate.
In an ideal world unfettered commenting on articles would be a great public debate, leading to shared enlightenment and harmony. Unfortunately most of them dissolve into a brawl. Just look at Techcrunch comments on anything mobile, or any posting even vaguely related to American politics. They all lead to disproportionate, unseemly outpourings of hate. Eventually that will be enough to prevent many people from discussing a topic, which may well be what the haters want. Not the suppression of debate, although some will, but not to have their views challenged.