What to do when another researcher used my results without credit in a science documentary?
I agree with your former advisor: let it slide...published information can be used by anyone in documentaries...[they] cannot cite everyone, perhaps even anyone, as this is not interesting, moreover, it's distracting. This applies not only to documentaries, but most manuscripts outside of academic publishing, e.g., textbooks, company reports, magazine articles, ... (That said, authors should ideally be able to produce sources.) Bask in the glory of having your work included, mention the media coverage on your CV, on your web page, in future research papers, etc.