For context: the Thai monarchy is entirely ceremonial. Protestors have been calling for reforms to end corruption, including a demand to end lese majeste which is often abused by politicians to silence opposition. The King himself didn’t press these charges (not that he isn’t a piece of sh-).
The woman who was sentenced is in her 60s – a generation that isn’t part of the reform movement – for merely sharing a post made by someone else. She’s losing her pension and spending the rest of her life in jail. This sentence was meant to terrorize the protesters into silence. It has nothing to do with the King.