When they're evacuating others, they're evacuating so that they can more definitely live another day.
When they're directly fighting, they're fighting for the chance to definately live as victors of the war.
Obviously your personal stance is going to be more one way or the other. The 'evacuators' might see directly fighting as relatively fruitless until the Crucible is completed.
And the 'fighters' might see any evacuations as relatively useless because the places they're evacuating too, will likely be overrun in time anyway.
That's just how this story works imo.
(Though I'm not saying that fighting in itself is bad. I'm talking about direct fighting whenever possible, which is something different. It's up to the individual player to decide just how much should be or should have been done. Some evacuating actions may be seen as pointless, like that scene where the soldier's daughter gets sent to..Thessia. Some direct fighting actions may be seen as fruitless, like.. everything that's being done to hold as much of Thessia as possible, when you know they're gonna lose.)