While you are certainly entitled to your opinion, this law is nothing more than knee-jerk legislation. It serves no real purpose.
It serves the purpose of outlawing handing automatic weapons to kids under 16.
Which is a good purpose.
And entirely consistent with other good laws we have banning giving dangerous things to kids.
So, while you're entitled to your opinion, absolutely this is a good law which may do some good and will do no harm.