This source is an example of an ideology that is the total opposite of nationalism.
The whole idea of nationalism is that your own country is better than other countries and has no need for their help or really for much interaction with them at all. Your country does its own thing and tries to make other countries do what it wants. It does not try to cooperate with them -- to the extent possible it just does what it wants.
This quote puts forth the idea that countries must work together for some common good. Nationalism rejects the idea of a common good. It is an "every country for itself" sort of an idea.