My dad is a contractor whose typical jobs last 6 months to a year. In his 35+ years of working, he's never had a contract longer than 3 years. Each and every time, every single boss and every single coworker treats him like an idiot, is intimidated by him, are all stupid and don't know what they're talking about, and life would just be easier if everyone did exactly has he said.
Every. Single. Person.
Now I fully believe there are a handful of idiots in the bunch. Of course there are, we all run into idiots in our lives. But someone above mentioned the common denominator. What's the likelihood that literally everyone he's ever worked with is an idiot?
I love my dad, but he's got his faults. He's far too proud and is not a team player in the slightest. His dream job would be to sit in a dark office with the door closed for 10 hours a day with his only social interaction with coworkers being them telling him how smart he is, and if he ever makes any suggestion for improvement everyone should trip over themselves to tell him how smart he is, because he is of course, the smartest.
You ask specifically about your boss but you use the term "they" a few times, so I'm guessing you're having issues with coworkers too. You've called yourself irritated, indignant, righteous, and arrogant (while saying you "try not to be" or "are working on it"). You can't change other people or how they respond to you, but you can change yourself. Or, you don't want to change yourself and continue to suffer your "toxic" boss. And sure, there's a chance your boss truly is an asshole. But I'd also say, given how you've represented yourself here, there's a fair chance that your boss or coworkers have written similar forum/blog/question regarding their "toxic" coworker.