"Like, why is it that a service man get "liberty" when he gets permission for leave."

Because government-supremacists (and other liars) like to pervert words to mean the opposite of what they mean so that people won't realize they are evil.

Take Thomas Jefferson's definition or description and compare it to mine:
"Rightful liberty is unobstructed action according to our will within limits drawn around us by the equal rights of others."
Doesn't that describe freedom tempered with responsibility to you?