because
"Your Honor" or "Mr. (Mrs.) Mayor"
Judges should be addressed, "your honor".
The proper greeting for a City Council President is President, or sir. If the name is not used, then Mr. President is an acceptable form of greeting.
The honorific would be The Honorable Councilman/woman John /Jane Doe, and the salutation is Dear Councilman/woman Doe.
The proper salutation for a probate judge is "The Honorable [Judge's Full Name]."
What is the proper salutation for a register of wills, e.g. Honorable John White?
The proper salutation when writing to a judge is "Dear Judge [Last Name]" or "Your Honor."
the correct salutation for two men is Messrs
Your Honor
Hello.
Dean actually is the proper salutation. One could say: Dean Redmond, would you please sign this form? Alternatively you could just use the Dr. salutation or the Professor salutation if those are appropriate, which they generally are.