After the defeat of the white star, the people of the Roan empire had become too dependent on their heros to deal with every trouble for them, especially Cale who was in the centre of everything. So to take all the burden off Cale's shoulders who was already sick, Alberu wanted to do something to make the people understand that their ex commander was only a human. But the people who didn't even understand when he stabbed his own heart, what even can be more moving than that?