Some abusive people just believe that this is what makes them tough and effective. Has nothing to do with someone else pressuring them.
I used to give benefit of the doubt in these situations and think it is external, until I seen with such managers up close and it turned out it was them and only them begin source of their own assholery. The external parties were just enabling.
I'm reality it creates a hostile work environment where burnout is high, morale is low, and projects take even longer to finish. It sacrifices all long term gains for short term results.