Bad grammar is disrespect.
Underlings have to swallow that disrespect. It is just a power game.
The next level is simply to insult everyone, and everyone will still remain submissive.
After all, you don't know the limits of your power until someone quits. So abuse people, exhibit outlandish public behavior, say racist or otherwise objectionable things...every person who remains on your payroll is a sign of how powerful you are.
This is not a common tactic, but it's a highly visible tactic, and it's not hard to find some notable examples out there right now.