I copy from this answer what the basis of parsec is:
They also use hours to measure time, which are just as Earth-centric. But remember, they don’t actually speak English in a galaxy far far away. Every word that is spoken on screen has been translated from the original language, so presumably the units have been translated into our units as well.
So, every unit is translated into a human measurement. It can be presumed that figures of speech are also translated. The name olive branch strengthens this:
The olive branch is a symbol of peace or victory allegedly deriving from the customs of ancient Greece, particularly regarding supplication to both the gods and persons in power and is found in most cultures of the Mediterranean basin.
From the Wikipedia article on Olive branch
So, the olive branch is an European / American figure of speech. It is very unlikely that they use the same figures of speech in a galaxy far, far away.