I’m not sure private security guards would be effective unless each home has its own.
Listening to Mr. McCloskey speak, I inferred that their subdivision / neighborhood has private security — but they never showed up to help. I think he said that neither the regular police, nor the private security, came to their rescue.
The scene from Godfather 2 where Batista had promised security for the mob investors, but “private security” of former and current military could not stop the tide of the mob. Unless you are willing to go at it like in Korea, it won’t help squat.