First of all, I have heard and read from numerous sources that I trust that slavery played a huge role in the early American economy. But that on its own would be a simple factual dispute.

The second issue is that regardless of the accuracy of the claim, downplaying the value of slavery is a way to devalue the debt owed to black Americans and has been used as such in arguments. The less valuable slavery was, the less white Americans should feel owed to pay back. So I think there’s a significant moral cost to this argument, and yes I think it’s disrespectful. But again, it’s factually controversial as well.

I had also made a variety of significant points which GP failed to respond to, instead focusing only on a hyper-literal interpretation of one subset of my argument. ¯\_(ツ)_/¯

The fact that England, another state with a horrific history of exploitation and colonialism, was also guilty of slavery, is hardly exculpatory for the US. Whether slavery was economically beneficial in every single historical example is a separate question from whether it was beneficial to the United States.