LOL Beau is the most obnoxious character in the history of cinema

You must be a female Millennial... Not to stereotype, but I must note that as such you are in a generation which seems predisposed to assume that the character was an evil misogynist. Oh, you also used the term sadistic.
All I can really say is Lighten Up! Don's character was directed to be rather over the top in terms of being obnoxious. But lighten up with the overtone that he was a psycho when really all that was trying to be portrayed is that he was naive and zealous with his approach to women.
Anyone with any age or half a brain knew that all the film intended was to suggest Beau was young, naive and quite overzealous. It was intended to be comedic, but it didn't always hit that mark as Don was directed poorly. But to sit there and offer condemnation on the level of that you had just watched a movie about a serial killer who abducted women is just silly reaching and shows your brainwashed, ultra PC, I need a cause to maintain the fact I am a feminist (and not the good or normal kind) and cast judgment on a film that was largely meant to be a comedy with a little drama and happy ending.

Might I suggest you simply do not watch movies that predate 1980.

good lord....

It's an absurd character, but that's how he was written (and directed!) Cherie, too, is ridiculous--she has no clue what a bad performer she is! It's not realistic, even for a 1950s film. But, it's not that Cherie or any of the other characters accept Bo's behavior. Everybody is appalled, and Cherie tries her best to escape and express herself in her limited capacity. (I love MM finally shrieking at him in rage, when he tears off her "tail." She very rarely had the chance to express aggression and anger onscreen.)

I blame Logan's direction. He also encouraged Marilyn to "project" in a kind of stagy manner. But that worked, because MM is always so soft-spoken it was refreshing to see her loud and exasperated.

It's not a film that has aged well, but with the exception of "Blondes" "Some Like it Hot" and (perhaps) "The Misfits" most of her movies haven't. She's great--or at least fascinating to watch--but the films themselves don't generally stand the test of time, are very much products of their era, and of her image. Studios--especially FOX--saw her as a living pin-up, rather than an actress, and her roles her often place her in that vein. Cherie, for all her absurdity, had a rich inner life, a history. Rare for an MM character.

Look, I stuck w TCM and watched "Rebel Without a Cause" right after "Bus Stop." Talk about dated and overwrought! Like "Bus Stop" it's a great looking film, excellent use of Cinemascope, but the to-the-balcony performances of Dean, Sal Mineo and (to a lesser extent) Natalie Wood, do not stand the test of time.

Also, for all those who say "Bus Stop" is so misogynist, please remember, Cherie, in an attempt to soothe Bo's bruised vanity, tells him she's led "a real wicked life" and he should be glad to be rid of her. He responds as few men--on or off screen--would: "I love you the way you are, I don't care how you got that way!" Very rare in a 50s film for a self-admitted promiscuous woman to have a happy ending.