A significant principle of the 'rule of law' and 'freedom under the law' for a long time has been that there should be no penalty without a law that imposes it. The principle is so old it was there in Latin too, "nulla poena sine lege", and some (including me) regard it as one of the important foundation-stones of a free society.
What the maxim didn't spell out (maybe because it was thought obvious, or should be) is that the law needs to be one that makes it clear and specific enough so that people know in advance what the penalty-earning conduct is going to be.
The ingenuity of some modern legislators subverts this principle while pretending to respect it. They design and pass blanket laws -- such as, arguably, the CFAA -- which are so broad, that they generically criminalize harmful and harmless conduct alike (or, harmful conduct along with other conduct that ought to be considered harmless except it goes against the interests of the legislators' friends). It seems to be assumed (occasionally said right out) that the harmless acts swept up into the breadth of the law will be treated as 'de minimis'. Then it is left to the discretion of prosecutors to pick the cases 'really' deserving of punishment.
Of course one big question about these blanket laws is whether prosecutors should be trusted with that kind of power (I'd answer 'no', and point to the recent Aaron Swartz case).
But an even bigger issue is that the result of subverting the principle of 'nulla poena sine lege' in this way is, that no-one really knows any more what conduct is going to be forbidden in practice. A whole lot of folk get theoretically criminalised for the harmless actions swept up into the over-broad laws, and can only rely on the legal system ignoring the 'de minimis' actions. This is obnoxious for so many reasons, including that harmless acts ought not to be criminalized even theoretically. But it is worse when the blanket law becomes used as justification or pretext for punishment when a prosecutor wants to really get nasty with somebody for some quite ulterior reason not made publicly known. Then the real motivation for punishment can become deceitfully concealed under a veneer of sanctimony '. . .but he broke the law'.
I can hardly think of any subversion of the legal system more poisonous to freedom and the rule of law than this.