Is "those" a demonstrative pronoun or a demonstrative adjective in this sentence?

It is a pronoun, because it replaces a noun. It stands for people or persons.

As an adjective it would have to determine a noun, but in our sentence it can't determine either routines or countries. It could be an adjective if it would determine an elided noun, but this would presuppose the presence of this noun earlier in the sentence. For example:

The routines of these operators are quite different from those (operators elided here) who live in other countries.

But in your phrase there is no ambiguity, it is definitely a pronoun.