Firstly many of the statues were erected and parks named, decades after the individuals had died, so hardly period appropriate regulation.
Secondly many of the ‘flawed’ attitudes were already being challenged as unacceptable while these individuals were alive.
America was built by countless millions of people, much of the work and wealth generation by slaves, so let’s celebrate those people, not their ‘flawed’ ‘owners’.
Perhaps the removal of the Native Americans is something more troubling.