I agree, what is going on!!
Prior to 2015ish, or so, in my experience, people weren't so razor sharp disagreeable.
It's really a beyond, night and day change. Most people I interact with, don't seem to be aware of it all, whether they are affected by it or not.
This leads me to believe that, we are all, to varying degrees, susceptible to this type of behavior, but that, external influences, like with anything, can magnify the state of mind.
Back in 2012 or so, I was quite sociable with all kinds of different people with different opinions; and the majority of the time, we were all too busy enjoying eachother in one way or another, to really even care about what our ideological/political/religious/etc.. differences were.
Just like the, Milgram Experiment
, I think a vast majority of us, the world over, are being stressed in a particular way, and it's causing an effect on the way we think/feel/behave/ and conduct ourselves...
What has changed since 2015ish? Artificial Intelligence has grown quite a bit since then and become more widespread in it's application (it's been used in, 'social media,' almost since it's inception), computerized cellular phones have become the norm, the economy has changed, and the geopolitical landscape has been altered quite a bit. I'm sure there are other changes...
If you look back to WW2, during that time, radio still relatively new, and had become commonplace for the first time in history, if I'm not mistaken.
I tend to think there is, 'something in the water,' to turn a phrase; that, combined with many of us, on a personal level, dealing with very similarly highly stressful living conditions and experiences, that, collectively, have altered the collective psychological/social climate.