In my opinion, it is not about the internet versus library research. it is about secondary data. It is about critical interpretation, mainly specific to discourse analysis. In this situation, I will go with classical terms: scientific literature interpretation, text interpretation, discourse analysis, and so on. If your sources, of course, are not doing research with the help of data mining, theme networking, or other specific methodologies for gathering and preparing data.
There are two different types of researches,one is based on the primary data and the other is based on secondary data. When research is based on primary data, researchers collect data using different methodologies as you mentioned. However, secondary research is based on published reports or data collected by other researchers. From your
example, it seems that the research is based on secondary data. This data can be accessed through library books or the internet.