I have a hard time imagining this fat bastard is the glue holding the entire kingdom together. His corruption might be holding together his court of lickspittles and enablers. (Anyone who let Joseph stay in power this whole time is also asking for a purge). And outside of his faction, there are other nobles able to rise up and take the reins; for better or for worse.
But not knowing if the next guy will be worse is a terrible reason to keep the current terrible guy in power. To review King Porkmouth's record, he:
- Kidnapped three magical superhumans
- Used slave magic to control them
- Broke multiple promises to them, in front of his court, tanking his trustworthiness rating
- All so he could use them to wage a war of aggression that would have resulted in thousands of pointless deaths
If the king's plan went well, he'd have been a tyrant who caused his people to hate him for the widespread destruction he caused. And the king's plan did NOT go well, resulting in three superhumans who hate him.
He gambled big, and he lost. He's a massive destabilizing force on his country. Simply letting him go invites civil war. Nah, when a regime fails this bad, you kill them off and clean up the mess.