Question: What can I do to develop my muscle for generating themes, purposes, and content, as very often I haven't used it, focusing mostly on style?

Answer: 
Copyright protects an arrangement of words, a "work", not the ideas behind that work. Even characters, while potentially protected by trademark, are not covered by copyright (though in a commercially published fiction of any consequence, especially one of a well-selling series or franchise, it's pretty likely the characters and some catch phrases will be trademarked -- don't try writing your own story around Mickey and Minny Mouse, or The Avengers!).

That said, news is about sources, as much as events; if your source is an article in another news outlet, you're writing at second (or worse) hand, and if you do this at all regularly, word will get out and consumers will buy from the agency with the originals, rather than the copies. New is also about timeliness, and if you write copies, they necessarily come out *after* the work you copied -- you got scooped!

In general, reputable news agencies will discipline employees who report this way -- and they'll catch them at it via fact-checking (a story needs to be verified against a reliable source before a major outlet will publish it).
I'm not a lawyer, but my understanding is copyright is about intellectual property. I created the idea, therefore I own it.

If a news outlet re-writes a story, they weren't there. They don't own the intellectual property. Somebody else does.

Why should I benefit from somebody else's work? If I re-write a novel using the same characters and story, I am stealing another person's ideas.