The internet creates the "wall mentality" in that two individuals sat opposite each other won't argue but if you built a giant wall defence between the two people they'd start expressing themselves in a different way, either more open and honest and or more aggressive.
Anger is a natural human emotion, in society we are suppressed to control this - but in environments such as Sport we can let it out.
I can be a right angry bastard but if you spoke with me after I've just spent an hour on the heavybag in the gym I'm one chilled out c*nt ;)
Throw in the "wall mentality" and this allows anyone to fight - resorting to childish behaviour merely just reflects their true inner self which they may suppress in places such as Family life and Work....
Researching the statistics of domestic violence highlights how angry Humans are, yet you may not see what's going on behind closed curtains.
On the Internet - you can read into what people truly want to say.
I remember watching a video which recorded what a load of Teenagers (probably your Sons) were shouting/screaming whilst playing online videogames using a microphone...
Their parents listened to these recordings and were shocked at how horrific the language being used was... Yet they did not know that the recordings were of their own children.
"Who has raised these children" was one of the comments made... It was you love!!!!
I have been guilty of being aggressive on here, one member was saying something or another and I offered to meet him as I just couldn't be bothered with the whole keyboard warrior thing... I'd rather just meet up, discuss his heart ache and maybe break his fingers :D (only joking)