When the Constitution was written, most people considered themselves citizens of their respective states first and only US citizens secondarily. Even with the "new" constitution of 1866 which now included the 13-14-15th amendments, that mindset didn't go away. As evidenced by the Rainbow Division- the 42nd Infantry Division tht first saw military action as the USA entered WW1 as Americans from the several states wanted THEIR men to be the first to enter the war.

One Supreme Court Justice once labeled states as laboratories of democracy. He's right but not for all the right reasons because in some states, that laboratory produced horrendous results: Jim Crow among others.

Simply put, in the USA, your rights should not vary due to your zip code