The police have their blue wall as we see evidenced countless times of late. But other workplaces do to. In one place I've worked, the union protected a bully who desperately needed to be fired.
Now I've observed it in colleagues the past few years that I've been poking around serious academia. I've seen it with tenured full professors, extensive publication records, attract lots of dollars, yet who, at the end of the day, remain out and out bullies prancing around like princes in their little fiefs. I've watched them do it other professors for whom English is not a first language, and I've seen them do it to their gradstudents even after they finish: Shout, insult, curse, and diminish.
It's a problem for the student because they rely on them for reference letters, and complaining to anyone would jeopardise that. In a small department where the bullies hold the key positions of redress, this becomes especially difficult. Furthermore, I've seen it where they also form the core 'boys club' which consists only of established faculty like themselves, and aspiring long-term male faculty who look up to that sort of loud braying as a mark of high manhood or some such shit. It's disturbing to watch the high school locker room dynamic playout with over-educated middle-aged adults.
You really want your ducks in a row to go against them and be prepared to either not finish your degree or lose the vital relationship that gradstudents have with former supervisors that's often required for continuing in academia. Having no reference letter from your supervisor looks really bad when applying for academic jobs or higher schooling.
So they stay, able to bully each generation because turnover rates mean there is little institutional memory. Morever, someone who brings millions to dollars in grants has a value to the institution that might trump the concerns of a mere student. Which of course the students know too well.