"some" implies more than one. There was only one. There weren't any more, and there doesn't seem to be any sign of more. And this happened in a city where people get shot to death every day.

Life is literally no less safe for CEOs in the US post-Mangione then prior. The whole narrative that he represented some kind of social or cultural inflection point against CEOs was simply false, and the ones that are actually afraid already hire security because getting kidnapped for ransom is a much bigger threat than being shot in the street.