Interesting I'm not a native English speaker but in news articles I have always interpreted "controversial" as meaning "under discussion" (perhaps even around a 50/50 divide) hence why they are writing an article about it.
I feel it is the news outlet trying to justify why the topic is important to read about since most people reading it will interpret the issue at hand as having a "common" stance. Usually it is used in topics that are very binary, for or against.
> Usually it is used in topics that are very binary, for or against.
It can be for those topics, but very rarely to describe the side of such topics with which they align.