Documentaries are a style of presentation that contain a directed, (usually) information-dense slice of a specific topic. It's an easy way to immediately engage in a topic in a manner that can present layman consumable information and establish context on potentially complicated subjects. It's one of many sources of information that should be supplemented with research based fact checking and information gathering.

There was no effort to dissuade further research yourself or to not engage with other mediums. I also don't believe they were supposing your only source of information should come from their casual suggestion. "I strongly suggest" you go ahead and link the research papers you've personally vetted like the poster above you trying to contribute to the discussion did that covers these topics indepth if you feel passionate about the lacking information.