Cmv: there is no obligation refer to nobility by their titles/honorifics.:
It is often appropriate to refer to individuals by honorifics such as "Doctor," "your honor," or "Captain." In certain situations it is considered disrespectful to not refer to a person by their honorifics\titles.

However, it is my position that nobility NEVER deserves to be referred to by their honorifics/titles (King, Queen, majesty, Prince, ect.). Why?

(1) Nobility is completely unearned. Nobility is something passed down through family lines. A doctor earns their title, a duke does not.
(2) The system of nobility is historically oppressive. Individuals who are nobles today have a lot of wealth based on a historical system in which a very small % of the population had unfair power over the rest of society. 

These two reasons remove all obligation to refer to nobility by their honorifics in any social context.