Simple

It was only a mission to do their jobs... no one wanted this to happen. Because there are some things worst than death, at least death would've granted him peace.

But instead a paladin is forced to suffer the horrible accident, the planet thinks of him as a hero, that sacrificed for their homes freedom... others see it as a time to get a replacement for him. But Voltron disagrees.

Until they find a solution of the war, an alliance with the galra. As the new ruler of the empire seeks peace rather than more graves. So they trust him only a little, some more than others.

But the paladin that suffers can hear the rumors but feels the truth... while he sees nothing.