Public violence in the news: why certain locations?

School shootings are big news. Terrorist violence also occurs in other public venues, but not others. There seem to be patterns.

Ride-share vehicles, for example, seem to be targeted as cites for atrocities, probably to spread fear so people will avoid them, yet we don't hear the same kinds of stories about traditional taxis for some reason; maybe because some perverse taxi company investors fund the bad press against ride-sharing.

Likewise, when is there ever a public shooting or other act of terror in retail shopping centers, stores, etc.? Are retail outlets somehow exempt from such terrorism, maybe because they generate commercial revenues for investors?

Or are mall cops just really good at preventing terrorism?