The retaliation missions are somewhat frustrating. How are you supposed to save civilians that are getting killed halfway across the map?
I know you're not asking for this but that's why, in my XCOM2+WotC run, I used the mod "Civilians Revamped". In the default game, the civilians just hunker down and wait to get shot down by the aliens, like sitting ducks. The mod changes this by making them run from the threats and/or seek cover (a more realistic behavior).
But I agree with Pladio here: just rescue 6 civilians and be done with the mission.