I think your post illustrates why the Rudins, Weinsteins, and (better mannered) Wintours rule the roost. You said you had a dream experience at a regional theatre. Sure, low stakes, non-profit, out of town. But where does "everyone" want to go? Broadway. So the competition on Broadway is brutal. Same thing in Hollywood or publishing. Everybody wants those jobs, so it's not a surprise that only the strong (nasty) survive. It's always been a bit of a truism that the boss, in a commercial marketplace, is a bit of a beast. That's how he/she got there. You see it in old movies and books: All About Eve, The Bad and the Beautiful and even The Carpetbaggers all tell us how a villainous person rose to the top.
I'm in no way defending Rudin. Just saying this is the way things are...and have been for a long time. Can it change? Only if everyone decides to work in regional theatre. Ambition is a human trait.