Re: Why go public?
And who is the intended receiver?
1. The Western public, because the story can be spun as evidence that "Russia is a threat to us all", and plays to the narrative that our governments are here to protect us, and have our best interests at heart.
2. The non-aligned world because (if they hear this, believe it, and care) it damages Russia and Putin's credibility and trustworthiness. In international relations, those two are vitally important. I'm not sure most of Russia's trading partners will care, and I suspect the relevance of the story to (say) the Chinese, Arabic or Indonesian citizens is small.
3. Putin. The hope is that he'll be embarrassed and be a big bit more cautious next time, to the extent of desisting from the unwanted behaviours. This would seem to be optimistic, since Putin will now be thinking that he needs to re-establish his strong man credentials by some show of force.