If someone grabs me and shouts at me, I'd say it's a reasonable reaction to believe that they intend to harm me. I don't know why you say that this "obviously wasn’t the case in the workplace" - people get assaulted and harmed in the workplace pretty commonly. The fact that the supervisor grabbed the employee IS the real issue - I'm really curious to know what you think "the real issues" are, if not aggressive, threatening behavior.

Tangentially: why do you assume that the employee is female?