But does this not open the way for arbitrariness? At this rate, given enough support in the congress, the executive power can pretty much do anything -- the congress will just decriminalize it afterwards.

Edit: What I meant in previous post was that a court of law has the possibility of absolving private actors or responsibility, the same way they do with someone who has committed an illegal action under blackmail: they are still guilty of having broken a law, but there are obvious reasons why they should not suffer the full penalty of it (or any penalty at all), and legal action moves against the blackmailer.