The Constitution was written to establish a framework for Government, the Bill of Rights, which is an actually an addendum to the Constitution, was completed to insure passage, and it itself has been amended twenty seven times since 1791. The fear of Government was largely mistrust of a strong central Government, especially by those States feeling overwhelmed but he NE States.
Your notion of it being written for “people to be free” is sophomoric at best, an over generalization that actually ridicules a complex document
To say the Constitution was