They built their business on the lowest form of tabloid clickbait that could possibly be imagined. You can't go from a position of 0 integrity, and then say "Hey, we're expanding into an integrity market. You're simply ignorant if you don't read our content".
Well, why not? The reporting is adhering to the normal standards of the profession and seems basically firewalled from the meme listicles. Even mainstream news organizations are borrowing a lot of those techniques for engagement anyway. And to return to the CBS example, they existed purely as entertainment for nearly a decade before introducing a regular news broadcast. They don't deserve complete, unquestioning trust, but what news source does?
CBS didn't have integrity issues as a broadcaster before expanding into news. Buzzfeed's entire business model has been based on no-integrity clickbait garbage, that's what their brand represents. It doesn't matter if they decide to hire a few "real journalists", or at least what they think "real journalists" are, they have no credibility at all.
Fortunately, they've documented where their claims come from, so you don't need to just trust them in this case. And I think your image of the edifying nature of early radio may be unfounded.