How do you conclude that from that PDF? It shows almost all of the states in the US in yellow (low mask usage). While almost all of Europe (except for the UK and Scandinavia) in blue (medium mask usage)

There's even a special call-out in the PDF about the US being such an outlier:

"US states and Canada stand out for their low levels of mask usage compared to many countries in Asia and South America. "

Yep, and the numbers are just as shitty.