I have a friend who claims that because the US wasn't serious about masks "This is why the rest of developed world has flattened the curve while the US was still showing an exponential growth in cases" He also acknowledges that the virus isn't that deadly so I don't need sources on that.

I need sources about why that isn't the case. Either analyzing the trends of other countries curves or about the US not actually having an extra trend. Information about masks not working also helps, but should probably be secondary.

Frankly I expect this to be about overreporting in the US and suspected cases being counted.

I have a friend who claims that because the US wasn't serious about masks "This is why the rest of developed world has flattened the curve while the US was still showing an exponential growth in cases"

I need sources about why that isn't the case. Either analyzing the trends of other countries curves or about the US not actually having an extra trend. Information about masks not working also helps, but should probably be secondary.

Frankly I expect this to be about overreporting in the US and suspected cases being counted.