There are a number of reasons for the arguments I believe
Often nuance is lost due to the nature of text based chat. That leads to misunderstandings and people getting irate
There are folk like me who find it very hard to let something lie – either a need to get the last word or a need to keep explaining. There are a good few of us and when two clash then the debate goes on for ever.
There there is the “internet policeman” who feels its their duty to correct things that folk type and will often be very abrupt and rude in doing so. They believe it is justifiable to put people down.
Then there is the funny guy whos humour simply does not work. What they think is a funny comment comes over as snippy and bitchy.
Some folk believe that you should act and react as you would in real life, not saying anything you wouldn’t to someones face, others think “its just the internet” and fire away. A recipe for clashes.
The vast majority of folk on here are decent people. Its often the limitations of a text based debate and the lack of social mores for internet debates that lead to the arguments.
Good post and pretty much sums it up with the addition of what aracer said that some just enjoy an argument, not that that’s a major problem!