So this book was published at a time when U.S. policy makers were in a clearly interventionist mood and the Cold War would rage on for several more decades. As it turns out, the particular copy I got was originally from the State Department library (even with a stamp indicating the book was first received 1955 or 1956, I can't quite tell which), then subsequently withdrawn. In the back there is a check-out slip well glued in, with no evidence that there was ever any other previous slip. It was checked out a grand total of one time.
So I guess nobody in the State Department was particularly interested in learning more about Latin American ideas of non-intervention.