Stanley Kowalski of Tennessee Williams' 1947 A Streetcar Named Desire, filmed in 1951 by Elia Kazan, was provoked. I am not making excuses for him, what he did was wrong, but Blanche did not help herself. It was about revenge.
Blanche (Vivien Leigh) compared him to an ape, uncivilized, violent, and brutish. She tried to persuade his wife to leave him. She did not realize he could hear her, true, but she was acted incredibly superior throughout. She put on airs and whisked through his home. She looked down on him and used derogatory language about his lineage. "I am not a Polack. People from Poland are called Poles, not Polacks,"asserted Stanley (Marlon Brando). Blanche knew he had a violent temper, which was part of the reason she was so desperate to get her sister away from him. He blamed Blanche for the growing estrangement between him and Stella, and did not care for her talking about the differences between Stella and Stanley's differences.
Aside from not caring for Stanley's manner and violent outbursts, Blanche obviously found him attractive, as her sister, Stella (Kim Hunter), did. In order to get out of Stanley's home and find a place for herself, Blanche planned on hooking onto Mitch (Karl Malden). Mitch was Stanley's friend, and Stanley decided that he would not let her get her claws into him too. Stanley had been suspicious of Blanche from the beginning, and after digging into her past, he was probably happy to find that she was not the innocent she tried to make herself out to be. He repeated his findings to Mitch, who he knew would not marry her after finding out. He then repeated the story of Blanche's escapades to Stella, revealing Blanche's hypocrisy. If it was a tossup between him and Blanche, he would make sure that no one would believe Blanche again. Plus, he had found her weakness.
He found out about how she brought in man after man to her bed, even a seventeen-year-old student of hers. Sexuality was her power, what she used to make herself feel better. He found a way to break her. The night he was alone with her, with his wife at the hospital in labor, where she could not protect her sister, he struck. He could see how far Blanche had fallen, lying not just to him but herself. He took her, and he broke her. His revenge was complete with her being shipped off to an asylum, after he had pushed her over the edge.