I will leave it as an exersize for the class to explain why it was impossible for the writer of Article IV, Section 2 to have expressed an intent that referred to the text of Amendments I-VIII, and yet perfectly possible for Bingham to have expressed that intent using the same phrase.
Privileges and immunities did not and do not refer to the Bill of Rights. I previously explained exactly what were the privileges and immunities of "citizens of the State" , and what were the privileges and immunities of "citizens of the United States".