OK I will give my 2 cents.
He was named Jesus as his birth.
But in
Acts 2:36 it says that God made him made Lord and Christ.
It is a completeness to pronounce his name along with his titles.
When I sign a check, I do not just use my first name, which would be technically correct, but I also add my last name to differentiate me from all the other people who also have my name.
when you say Jesus, you are not completely indicating him, unless you add his titles.