I'd describe it more along the lines of there only being so many hours in a day, and only a subset of those that journalists are paid for. It simply isn't necessarily possible to cover every crime, political choice, special event, upcoming event, and more, with the nuance it likely deserves.
Your objection, to me at least, reads more like a complaint about journalists not putting every action in and by the city front and center. But if everything is front and center, does that mean everything is, or nothing? We get into a lack of space on the front page, lack of time to read it, and lack of places to put up notices that are essential. We essentially run into what Arthur Dent did in The Hitchhiker's Guide to the Galaxy [0], with "essential news" buried because something more essential was already there.
Regarding realtime use of Citizen that you described below, that doesn't sound like a bad use-case. I know it's not for me though. Having every incident sent via push notification (which I can only assume will occur on a long enough timeline to increase engagement) doesn't sound good for anyone's mental health. We may not be there yet, but I'm not sure I want to partake in encouraging society moving in that direction.
[0] https://www.goodreads.com/quotes/40705-but-the-plans-were-on...
Of course we should be sensitive to victims and I don't think sensationalizing things is beneficial, but I also think that most of what I personally use Citizen for is to figure out what is happening near me in the neighborhood in real time. Like, "why is it suddenly smoky outside," or, "why are there a lot of police helicopters flying over us right now?"