Who had the problem? The nut, or Society?
Frankly? A little bit of both. We are all a product of society.
The "nut" had issues with society.
The reprehensible way he chose to deal with those is solely on his shoulders.
However, let's look at some of the messages society sends out regularly.
At school if you're not good at sports you're a loser.
If you're not in the "in" crowd you're a geek.
Later in life if you're not a success, you're a failure.
You're single and in your late 20's? Oh dear: well, I'm sure something will come along. Surely there's someone out there for you...
If you're with someone for more than a year or two and you haven't tied the knot you're not committed.
Live with your parents? You're a waster.
Don't have an iPhone 12? You're uncool.
Exaggerations? Perhaps? Stereotypes? To a point.
All I'm saying is that these social attitudes and judgements are not new and I think these kinds of societal expectations do hang heavy on some. And a percentage of those develop major self-worth complexes and some of those then lash out. Lashing out is not justified. But are those societal expectations? Do they really bring anything to the table? That is what I mean by the issue conformity.
I'm not however defending their actions.
Feel belittled, disrespected? Go to a self-help course. Do something to bolster your self esteem. Realise and understand that other people's opinions don't matter in the slightest!
There are a hundred more productive ways to deal with angst than shooting people in a pathetic attempt to garner some sort of respect or awe.