To unlock the "MORAL VICTORY" trophy in Detroit: Become Human, you must successfully get the soldiers to back off during the game's final chapter "BATTLE FOR DETROIT".
Below is one potential playthrough that leads to this outcome. There will probably be several and I will update this guide when more information becomes apparent.
*** Spoiler - click to reveal ***-- Public perception of the androids is generally sympathetic going into the final chapter.
-- Connor has turned deviant.
-- Jericho has been detonated going into the final chapter.
-- Markus chooses to spare Connor and conduct a peaceful demonstration going into the final chapter.
-- Markus continues to walk towards the soldiers peacefully, and sits or raises his hands.
-- Markus does not leave the barricade to talk to the FBI.
-- Markus raises a flag in the barricade.
-- Markus chooses "FREE" or "ALIVE" in his message to the journalists.
-- Connor successfully converts all the androids at CyberLife.
-- Markus successfully passes the QTEs when the barricade is attacked.
-- Markus decides to sing at the soldiers at the end of the fight. (If you have developed a relationship with North, the Kiss option should also save you as long as everything else has occurred)
Assuming the soldiers stand down in the final chapter, the trophy will unlock when you reach the final flowcharts after the credits roll.