On Ali (ra) And Muawiya (ra): Prioritizing Peace Over Justice And Vice Versa
That was not about justice and peace, but peace and chaos that would emerge in the case of Shura as people could never agree upon any single person. Justice had already been denied when the murderers got immunity under the flag of Hazrat Ali. However, all those murderers were killed during the battles and when the power came in the hand of Hazrat Muawiah it was the question of peace or chaos. So he preferred to maintain peace.