Founding Fathers' atrocious acts against natives have almost completely wiped out the culture(s)

Not to exonerate the so-called Founding Fathers - the American government has treated and still continues to treat the first nations horribly - but most Amerindigens died from the diseases they brought, such as small pox and tuberculosis. I've seen estimates from 50-90%!

Few cultures can survive such loses. They were doomed even if the Europeans had wanted to treat them with respect.