See:
https://github.com/straup/naturalearth-tools
Specifically:
+no_defs +over
Are you using the latest data on the site? That error should have been fixed in the data.
Thanks for the suggestion. I am using the latest data on the site.
Further research has indicated there may be a floating point precision issue with the chain of tools I was using. I ran shp2pgsql again without the -G flag (to create a geometry column instead of a geography column). Looking at the geometry data showed the points clipped to exactly 180. At that point, I was able to successfully cast the geometry column into a geography column without hitting the out-of-bounds error. Still not sure exactly why the shp2pgsql tool could not write to a geography column directly, but it can be worked around.
Thanks for the update. I’ll have to give that a try!