I know of time management software for public computers that have, as a secondary feature, the ability for staff to see what is on any particular computer's screen. This feature is certainly not the main focus of the software, and I never even thought of it as "spy" software before.
It certainly could be used that way, though; just like every car can be used to kill people. So what produces guilt: ability, intent or deed?
I would take this person's letter a lot more seriously if he didn't characterize the police presence in the library as "a Lakewood police officer, carrying a gun, stationed in both libraries, to shoot people. Why else do they carry guns?"
I seriously doubt that a police officer would be allowed to preform his/her duty without the standard-issue sidearm. It's not like the library has a choice in whether or not they carry guns.
Anyway, this was just a humorous article. I can't tell if it is sincere or a parody, but it shows how the simplest things can be twisted into something sinister with very little effort. "Knowledge Illuminates Opportunity" indeed.