And apparently he isn't doing so? He's just imprisoning those who disagree with him, not everyone around him. That's standard practice for a king. You'd have to be a fucking naive idiot to keep a bunch of people who strongly disagree with you in a political system where assassinations are the norm. This is necessary for his rule to function.
Let's say America was a monarchy and Donald Trump was king. Do you think it would be stupid for Donald to imprison liberals and other opponents to his rule? Of course not! It's necessary for such a government to function. Donald isn't just protecting his country, he's protecting his own very well-being and would blame him for doing so? Of course not, everyone wants to be safe and sound, even monarchs.
This is just the beginning, successful or unsuccessful rule comes after the dirty work.