Mutually Assured Destruction has been a succesful deterent to the use of nucular weapons for 70 years.
My suspicion is that the school arrangement with the Broward County Sheriff’s Department was that they were prohibited from entering the building wearing sidearms. Added to this was the lenient disciplinary policies of this school when it came to serious criminal activity an attitude of “Why Bother” set in with individual law enforcement officers.of that department when it came to dealing with that institution.
Only a full fledged review of these polices and public exposure to them will change this but they way this is being handled it will never happen