Televisions, vending machines, and computers are put in schools to distract people.
In a school environment televisions and computers are educational aids, vending machines are merely a convenience and source of revenue. If you don't understand that you belong in a facility for retards, rather than in mainstream education.

They want to keep the kids away from things like free will and critical thinking.
There is no such thing as "free will" only discipline and criminal responsibility. Better learn those carefully, or you will be a total fail in life and/or spend most of it in the big house.

Critical thinking is what most middle and higher education is about. It cannot really be taught as such as it is mostly an innate quality; only encouraged and enhanced.

You can't "teach" them responsibility when they're not even in control of their own actions.
Oh but you can, and you had better do it before a court of law does

They tell you to "Shhh..." in libraries because that sort of thing is taboo.
Well, this may come as a shock, but the word "library" comes from the Latin "libris" which means "book". You actually read books and most of us have mastered the art of doing this silently. If you haven't you are more of a distraction than all the televisions, vending machines and computers that you mention.

There is no such thing as "security" without a TRUE zero trust security model.
There is no such thing as a true zero trust security's like three people keeping a will only work if you kill the other two.

Otherwise you're just drawing an invisible line and asking them not to cross.
Most laws are invisible lines if you want to look at it that way; and you are not "asking", you are telling.