What are your reasons for disagreeing? I believe you said you're in security? I'd love to hear your take and/or ideas
This is a funny area for me and I admit right off the bat that I will voice some contradictions here.
First - anything can be secured. Period.
Second - securing anything has a cost. This cost is both financial and practical. Schools are a great example. If i were to peg current school security at a percentage I would put it at about 40%. To get it to 80% is pretty cost effective and has little practical impact. To get to 100% would be massively expensive and would have horrible practical impacts (think strip searches for kids).
Now, what you reference in terms of using security devices to prevent crimes...
Public spaces change the calculus. You cannot secure a public space through devices. Devices in a public spaces do not stop crime. Devices provide excellent evidentiary sources but not without compromises. That camera that is on the corner might be great at capturing who stole a car, but at the same time it captures EVERYTHING else that we hold private and dear. Sit on the bench with your girlfriend? Play basketball with your buddies? Pick your nose at the stop light? None of this is relevant yet it is all captured, stored, and analyzed. This is not the behavior of a healthy society.