Either that, or they're just clinically certifiable narcissists. True narcissists are world-class pains in the ass like nothing else on the many spectra of personality disorders.
The same can be said about all sociopaths, they are all a very charming bunch.
The same goes for various other personality traits. If someone refuses to trust anybody else they likely can't be trusted themselves; I've seen it myself several times.
I agree the world is not divided into jerks/nice people. There's a spectrum. Try to stay on the nice side. You can't always avoid jerks but one should not go out of their way to be around them.
Always a good idea to consider that the other person isn't having the same day/thoughts/experience as you.
Empathy is much better than judgment especially in a situation with imperfect information.
I always try to give the benefit of the doubt. I can think of plenty of times where I only realize after the fact that I was distracted/in a bad mood and unduly acted rude towards someone.
While what you say may be true, in this case, it does not sound like he's convinced he's surrounded by assholes. Rather that during the few times he's encountered them, he simply decided not to put up with their behavior.
Actual Point: The reason I am hesitant about following the advice of this article is that it encourages you to divide the world into jerks and nice people. It's very easy to be a jerk to a jerk. If you are a jerk to a jerk, suddenly everyone on the project has to deal with two jerks.
I do agree that there are behaviors that just shouldn't be accepted, and there are lots of examples of them online. But you (2) do need to be mindful of your response to those behaviors. Make sure your response isn't to engage in those behaviors yourself.
(1 & 2) and by you, I mostly mean me. I am totally writing to myself here.