You don't even have to say bombs, the article lists a great example. They are tracking protests. I think I would like to be aware if where I normally deliver mail I'm walking into a protest that might get violent.
The FBI (or some other agency) can investigate these things and send out notices to government agencies operating in the area. It seems like you are advocating for every single government agency to monitor the internet for potential protests in their area? Why duplicate the work when we can get people who are experts handle it?