The sites shield themselves from search engines, so they do not pop up in response to online searches for the brands they offer.

Branded to non-branded keyword mix - if all you're getting is branded search traffic, you'll want to conduct a technical and content SEO audit of your site as something is probably not in order.

With a website this rich in content and from so recognizable a brand the designers could assume that the majority of traffic to these articles would come from search engines.