It seems like the rest of the party didn't have faith in him. He jumped the gun for personal reasons, while it would have cost the judiciary and politicians more than it would benefit.
This is kinda what happened when Trump lost the 2020 election. AG Bill Barr was probably down with a dictatorship, but he also knew that Trump wasn't gonna pull it off then. If Trump tried to overturn that election, the military would have stopped him and the public perception would sour. By holding Trump back from a more radical conflict that might actually bar him from running again, Trump was able to come back for the same reasons that he won in 2016.
If President Moon gets removed, the opposition party might come into greater conflict with Trump because they're less enthusiastic about licking America's boot. Trump will likely stop protecting them against North Korea unless they agree to unreasonable demands, as he tries to avoid such defense obligations. He might leave no matter what, but Moon will probably return to power anyways in 2026 on a platform of getting support from America.
He needs to be barred from holding office, or South Korea will be the next liberal democracy to fail from inside.