Why does Smith call Morpheus by his rebel name

Smith seems predisposed (and takes enjoyment) in deadbaming Zion rebels.

He calls Neo "Mr. Anderson" and Cypher "Mr. Reagan".

It's a pretty ingenious way of taking his opponents off guard and belittle them with names tied to their bandage.

Yet, during the interrogation scene in the first film he never calls Morpheus by his name.

He either respected him or his birth name actually is Morpheus.