You are right about the link between the slave economy and slavery to most
historic homes.  The problem with the way histroy is presented in film
(mostly fantasy disguised as history) and basic textbooks is that people
(mostly in the dominant culture but in minority groups as well) are very
uncomfortable with the truth.  When I was in highschool my teacher had
"laryngitis" the day that the lecture covered Richard I (the Lion Heart).
She did not want the controversy surrounding the great military leader's
sexuality to come up and found this way to not speak the words "he is
believed to have been what is now termed a homosexual" or something to
that effect.  Virtually all North Americans whose origins in the country
predate 1850 have benefited from slavery because of the unequal advantage
in accumulating property and wealth that was then bequeathed to the
following generations.  This does not even begin to address the issue of
the blatant theft from Native American Indians which also continues to
benefit all non-Native American Indians in the Americas.  I don't know
that I bear a personal responsibility to right every wrong but I certainly
do bear a personal responsibility to never forget the advantages of being
born  to this inheritance.  Problem:  how then can I carry out this
responsibility in my work?  Solution (this far and still a work in
progress) stay open, welcome the marginalized, face adverse reaction but
keep uttering the truth.