Ed. cleared up phrasing around new use, replaced meaning with use for .. meaning.
Which founding principles, exactly? Your comment seems to imply you think we should live in a world where we are only allowed to pick our actions from an enumerated list of approved actions. That world is extremely contrary to the kind of world I would like to live in, but also seems to contradict most of what I know about the history of the western world. Is that really what you mean?
I'm fairly certain that's not what OP meant, no.
What OP is getting at is that the common law tradition isn't to explicitly spell out all the nuances of when that action is actually disallowed, but rather to set out the general principles, and let case law define the precise limits of that boundary. In contrast, the civil law tradition is very much based on statutory law explicitly setting the boundaries, and case law serving only to disambiguate.
The "aggressive and putative new use" they're referring to is basically taking common law's fuzzy boundaries and pushing a civil law interpretation on top where all the grey areas are assumed to be allowed.
That is exactly how things work. Unless the government goes through the effort of passing a law to prohibit something (and getting approval of the people's elected representatives, and the courts), then the thing is legal. How else do you propose things should work?
Then there's the issue of marketing/propaganda (which the parent mentions as "hammered") whose sole purpose it's to change people's minds in an emotional way. I wish people would learn about Edward Bernays, nephew of Freud, who instituted this. In and of itself, propaganda has never been illegal, but no one likes to admit to being emotionally manipulated. (But when you begin to pay attention to your emotions, you can spot this stuff from a mile away).
Also, it's important to note that humans are actually quite bad at this sort of judgement. I'm sure if you showed everyone in Germany in 1980 a computer, and how it can instantly store and retrieve files and documents, and asked them 'is this moral?' they would be against it on the grounds that it would put hundreds of office workers out of a job.
It's the job of the judiciary to interpret the laws in these situations, and part of that is looking at the spirit of the law and create case law which may alter the powers of government.
This is very much part of the Western tradition of common law, as is a vigorous discussion over how far the judiciary should be able to go. It's fair to say popular sentiment has drifted in a libertine direction over the last 50 years, but the debate is far from settled.
(In fact we can speculate with some reliability about what the future may hold: via one mechanism or another, including the judiciary, governments usually trend more libertine in times of peace and more authoritarian in times of crisis.)
Computer programs suffer all of this as well :)