What commenters never seem to understand is that the "press" are commercial for profit ventures, and to a first approximation get paid for page views (on dead trees or web sites). It is in their interest to publish whatever furthers that goal, up to the point they drive readers away.
If readers punished the press for this then they would stop doing it. But readers don't, and as such the stories in the press reflect on what people want to read. And as much as people claim to be high and mighty, only want good news etc, they actually read all the salacious erroneous stuff.
This mis-characterizes the article. "Correlation is not causation" can be said about anything. The article has a number of specific findings which weaken the original finding.
Just about every strong and weak scientific finding involves correlation. "Correlation is not causation" comes into play most strongly when a correlation seems assign causation to something with no clear underlying physical mechanism - leap years and stock market behavior, etc. But one could imagine a number of plausible physical mechanism whereby sitting could be back bad for one. That still doesn't prove it but it different lines of reasoning could appropriate.
But the obvious correlation is that of the million situations that could cause someone to sit more, more of them lead to early death than extended life. For example, asthma, arteriosclerosis, and obesity are known to lead to both situations.
When a study comes out that exhaustively controls for at least all of known factors that cause both situations being correlated, give me a call.
If readers punished the press for this then they would stop doing it. But readers don't, and as such the stories in the press reflect on what people want to read. And as much as people claim to be high and mighty, only want good news etc, they actually read all the salacious erroneous stuff.