I'm not talking about "drawing conclusions from a single point of data". I'm talking about using single points of data to interrogate the completeness and correctness of your data.
You’re correct that the approach can be misused. However, it’s also worth thinking of it like a “persona” in product design. When used correctly the journalist has the data, the data tell a story, the journalist chooses a subject that personifies the story so people care to read about it.
The problem I see is that a lot (I believe) of people still do this, even if you and I don't.
I guess I'll contradict myself with the anecdote (I recognize this is totally not representative). I've heard a lot of stories about how "they do this and that, somewhere" based on a news about some single case. Some make sense, but also lots of variants of vaccines and autism stories (mostly, regarding modern politics, so I don't want to describe anything in particular).