Why Buddha didn't want him to be called 'friend' by the monks?

Referring these lines from 'The Discourse to Prince Bodhi ': > As I approached, Prince, the group-of-five monks were unable to > continue with their own agreement, and after coming out to meet me, > some took my bowl and robe, some prepared the seat, some placed the > water for washing the feet. > > Then they addressed me by name and with the word ‘friend’. > > When this was said, Prince, I said this to the group-of-five monks: > “Do not address the Gracious One, monks, by name and by the word > ‘friend’, the Realised One, monks, is a Worthy One, a Perfect > Sambuddha. Lend an ear, monks,........" Is it wise to get respect by compulsion? Is it wise to claim "I am The Greatest/Perfect One" even if you're The Greatest/Perfect One ? If that's OK, then why did he call his teachers Ālāra Kālāma and Uddaka Rāmaputta as 'friend' even before he started learning from them? How can this be justified?