why do so many discussions turn contentious?

All blogs contain some vicious people, empowered by the anonymous nature of it. I learned long ago, through blogs other than audiogon, to simply ignore them. It actually carries much more weight than arguing with them. They do not like to be ignored :)
If you let them get to you, find another way to communicate than through blogs is my advice. 

My personal opinion is that the internet (and social media especially) has empowered those whose personality disorders would have previously held them shunned.

Said another way, everybody has a poisonous uncle or neighbor that everybody knows to avoid, but on the internet there’s an endless supply and no way to avoid them. Scarier yet is that all the poisonous ones seem to find each other as kindred spirits and are emboldened.

As a society we haven’t evolved fast enough to keep up with it.

It is the way of the “new world reset”. I liked to watch sit coms until they turned into social engineering so I quit watching them. I liked to watch sports as a get away for all the political bs on the news and tv. As soon as sports brought in the politics thanks to espn I quite watching sports. Whats left music, yes we all know through history musicians have made political statements but the difference was that music was trying to unite the people to push back against a tyrannical government. Difference now is that instead of uniting they are intent in dividing us and most modern musicians are now supporting the tyrannical governments. Case in point U2 I use to enjoy their music but tried to watch a concert and turned it off 30 min in. Was not going to listen to a billionaire tell me that everything in the world is my fault because I have worked my ass off to be where I am today and I do not want to give my hard earned earning to dead beats or billionaire politicians. I do enjoy this forum and when a link turns I just move on to the next one. Once there is no next one I will be done with the forum!