The Eldars' surrender was perfectly normal.
The allies amongst the Combined Fleet had been silent as well when they saw Joshua mold a sun out of thin air—every crewmember searched their feelings then, and realized that against such a magnitude of power, surrendering was actually not a matter that affects courage or loyalty. Even Yana Milo, a Glorious Era Legend who had seen much looked on blankly, mumbling unintelligibly to herself.
To not simply faint made evident courage and hope in oneself… In other words, it was very kind for the warrior to grant the Eldars the chance to display their spirit.
