“They are very angry people. Rush Limbaugh emphasized that they are very unhappy.”
Yes, but what are they angry at and why?
I boil that down to the following:
1 - They are angry at reality, the world as it is
2 - And the reason is because they see reality as “unfair”. They just cannot stomach the reality that people are unequal, that some are smart, some dumb, some successful, some failures, some beautiful some ugly, some rich some poor...
This “unfairness” is an assault to their warped and delusional sense of “justice”, and it sends them on endless crusades to eliminate the reality of “inequality”.
It’s what today’s “equity” crusade is all about. It’s delusionals insisting and demanding that their delusions be made into reality.
So those that have concluded that liberalism/leftism is a mental disorder are absolutely right. More specifically, the disorder is a delusional disorder.
Thus, when you boil it down to its essence the struggle between right and left is literally one between sanity and insanity.
And you don’t solve a mental disorder by arguing or discussing differences, because that simply won’t work. They need psychiatric help.
And at a societal level, the sane people must take control, and keep the delusionals from running the asylum, as they are currently doing.
This begs another very important question, how have the insane managed to take control over the sane?

>> And the reason is because they see reality as “unfair” <<
Back in the days of Christendom, we knew what to do about unfairness: be grateful and give back (ie, noblesse oblige).
We no longer have the idea that “from those to whom much is given much is expected.”
Some are not too bad and do try to give back in money or time, others not so much.