Of course, the Emperor did not really want them to kill or capture all 130,000 rebels. He did have this wish, but it was 200,000 troops against 130,000 rebels. Not to mention how much military supplies and rations they needed, they could not afford to waste the time.
The Emperor just wanted to give those rebels a warning so that they would obediently accept the amnesty and recruitment. After all, if they really fought, their losses would be huge. If they forced those people to fight to the death with them, there would probably be an ongoing war in the next three to four years. While those people could focus on fighting to the death with them, the Imperial Court still had many concerns.