If Luo Lan continued to be so kind and soft-hearted, her authority would slowly be stolen by the Black Gold tribes. At that point, it would be even more difficult for her to solve issues.
She could only change the situation if she used Lin Yuan's Eternal Weapon to kill a large group of people and rebuild the system, just like what had happened in the Great Lush Federation.
However, this would come at much too high a price. It would result in the Iron Hammer Federation, which was already weaker than the other two federations, to continue being at a disadvantage.
Furthermore, Su Yiren and Luo Lan were on such good terms because they had similar pasts and because Su Yiren wanted to use Luo Lan's faction to help to revive and bring glory back to the Seven States of Darkness.
Hence, it went without saying that the more secure Luo Lan's authority was, the better it would be.