This article says they did.
https://www.npca.org/articles/2309-exploring-70-centuries-of-mining-history
Says "they did" what? Here is what I saw in the article you linked to:
Starting around 7,000 years ago, Native Americans shaped the copper into tools, fishhooks, jewelry and other implements.
I have a friend who may have the largest private collection of old copper culture artifacts.
None of them were cast. They were all cold worked to shape.
Many people have wondered at the lack of smelting and casting technique. Smelting and casting requires the melting of the copper, so it can be cast into desired shapes.
No evidence of smelting has been discovered, or if it has, it has not been understood.
If it were used, you would expect lots of cast copper implements.
Instead, we see lots of cold-worked copper implements, and no evidence of casting.