The Monroe Doctrine, in sum, is USA domination of South America.
This also is the truth on the ground. Any country that doesn't subject to the USA is constantly harassed (e.g. Cuba, Venezuela at present).
So whether the Monroe Doctrine is on state.gov or not, is immaterial. In reality, it is how the foreign policy works.
As for the oligarchs, they control the politicans. Then the government goes and carries out *their* will, not the will of the public.