The notable historian Eddie Izzard made a compelling argument about how the British Empire employed the cunning use of flags to bring people under their rule.
Capitalism is when I own all the tools, and someone else does the labor in return for a small portion of the trade receipts. If the first nations people did that, then sure, the were proto-capitalists.
We have little to no evidence that this was the case. Unfortunately, we do have evidence that the first nations were settled, agrarian societies before smallpox and company were introduced. That's what De Soto describes encountering 100 years before the English document that the first nations peoples live as roving hunter gatherers. Because our written historical record was only able to record what amounts to a post-apocalyptic society, and the first nations kept little written records themselves, there's so much about Native America that we just won't ever be sure about.
I think it is only about the meme(?) and how the premise of the content is wrong and through that any discussion about the argument itself is pointless.
Your criticism is valid but it's based on accepting the premise that they already rejected.
