the simple fact is that legislation is not usually based on data. there is evidence of it everywhere.

a senator of my state, who is also an engineer (like myself), said in a speech a year or so ago: (I am going to paraphrase it)

Almost all legislators have a background in law. Most are lawyers.
The difference between an engineer and a lawyer is this:
An engineer looks at the facts and uses them to form an opinion.
A lawyer forms an opinion and then hunts for facts to back it up - if necessary.

Many laws are what I call 'feelgood legislation'. The herp laws fall firmly in that category.