It’s deeper than that. You shouldn’t have to pledge allegiance to any system or set of beliefs in a country that claims to enshrine free thought.

There’s nothing more American, in principal, than seeking to change America for the better.

How ridiculous would it have been for civil rights leaders to have pledged to preserve the America that existed till the mid 60s.

The pledge, or similar, is almost unique to the US and other authoritarian states.