Absolute lunacy. If you are going to be a terrorist at least target something big and important.
In the security space this sort of attack is referred to as 'resilience targeting', as it impacts a community resource and each such episode (even when it's a hoax) imposes a not-insignificant economic cost - shutdown of the facility, use of police resources to cordon off, sweep, and investigate the hoax threat. It's hard to assess exactly how much but I'd imagine it runs into the tens of thousands of $ per incident.
A similar phenomenon is the wave of computer-generated hoax active shooter calls against schools, a pattern which has prepeated in multiple states over the last year or two, eg https://www.cbsnews.com/pittsburgh/live-updates/police-acros...
quite possibly only a single lunatic