The way groups of disadvantaged (or oppressed) people have overcome their situations is to move forward and develop adaptive strategies and behaviors. The best way to overcome is certainly not to obsess over the plight of ancestors. Many people that came to this country were poor and/or oppressed, thats why they came here. The degree may not be the same, agreed. Slavery was aweful but aweful for everyone, the Africans who chose and sold slaves, the multi-nation traders, and the slave owners.
There would also be less resentment going forward if groups of people did not focus as much as historical wrongs. We have acknowledged (and teach) about the ills of racism in this country.