That is not a map of US airspace, and I wonder very severely at your motivation for claiming that it is.
That is a map of responsibility for air traffic control/flight information services. The US has a responsibility to provide those services across a huge region of the Pacific; probably because they're the only large country with presence in that region. They charge for these services for aircraft which are not otherwise subject to US taxes.
The Atlantic is a little more interesting as it appears to cover the Bahamas; but one surmises that the majority of traffic in the region is nevertheless bound for the US East coast (note how it avoids Canada-Europe route sharply, and only protrudes into the Caribbean around PR).
I found a map for that https://www.faa.gov/about/office_org/headquarters_offices/ab...