Its a concept, make your protagonist a bad guy and it adds layers to the entertainment.
I think this is certainly more interesting than a good guy with no flaws, or geek that gets the girl. TV & movies were largely this way for awhile and rightfully moved away from it.
Its a study of the human condition, its sometimes more interesting if you do not identify with characters or their plight.
Mare of Eastown was just about a perfect example of the next evolution. Kate Winslett's Mare was a flawed character but in human ways, she makes mistakes, is awkward and normal looking. She does at least one very bad thing but not out of malice or evil, just succumbs to putting her own interests above others, something we all do at times.