"what use did a servant have..."

This quote depicts discrimination against different ethnicities because Hassan is now mentioned as a servant by Amir. This shows that despite the friendship Amir and Hassan has between them, the cultural value of Hazaras having a lower social status still has a role in friendship. Although Amir is able to accept Hassan, that does not mean that the difference in social status is not evident. Amir still finds Hassan different and therefore inevitably describes Hassan as a servant where words are of no use because it is the truth that Afghan society have made it so Hazaras cannot read.