Well, your use of the word "irrational" is for a very specific definition of rational. The German legal system is said to draw on the roman tradition, so there'

Well, your use of the word "irrational" is for a very specific definition of rational. The German legal system is said to draw on the roman tradition, so there's about 2000 years of development in this. Some of the concepts of rationality might be more correct, but they are comparatively very young. I also think you are overestimating our ability to rationally observe, understand and predict things in society. Part of the reason why we have these laws is that it is so incredibly hard to predict the outcomes of any intervention. Of course there is the threat of over-reach, but it's always there. On the other hand, we have plenty examples where lack of regulation lead to massive harm (environmental pollution, medical experiments, monopolies etc). So there is no easy solution, and "irrational" regulation is definitely on the spectrum of sane ones. Evidence-based policy-making is rare because there is lots of policy-based evidence-making.