Do something.... anything....
Whenever something bad happens, or is percieved to have happened, politicians need to be seen to be doing something.... anything...
What they do need not actually have any positive effect. It just has to push the right buttons with the citizens to placate them.
That's why government is incremental.We very rarely see them saying a rule does not work, or is pointless, so they strike it. Generally the best they do is tweak it. That is all governments - the world over.
That's how we end up with daft laws that permit the use of headsets when driving when they are as distracting as hand held phones which are banned.
Does having gun licensing reduce gun crime? Maybe, ut unlikely by much. Criminals don't bother themselves with licenses etc. Toff paying 10 quid per year seldom rob banks. But what it does do is placate a whole swath of anti-gun people who tut-tut that at least it is better than in USA where any maniac can get gun.
Of course they don't realise that USA has a vast amount of gun laws - restricting all sorts of things - many seemingly very stupid. You can buy a whole rifle at Wallmart, but you need a federal firearms license to buy some parts (triggers, bolts,...).
In USA you need a special $200 permit to buy a supressor. In Australia they are illegal. In UK you can get it one with a regular license. In NZ they are unrestricted - anyone can buy one through the post or in a shop.
As a license holding NZ gun owner, I don't mind the idea of a gun license at all - even though it costs be about $10NZ per year. It does perhaps weed out some nutters, but mainly it makes the naysayers happy so they get out of my hair.