I got done for speeding the other day, the ticket said it contrary to Sections
81(1) and 89(1) of the road Traffic Regulation Act
1984 and Schedule
2 of the Road Traffic Offenders Act
The details are online so I can look at the relevant sections and see if I did break the law. (I did, I'm guilty.)
That's how the law works, they need to tell you what bit of the law says something is legal or not.
It's very easy to say something is illegal and if they truly believe it is they will be able to provide those details.
Just providing those details doesn't mean they're right, it means you can check them out and see if you agree with their interpretation.
I used to work for the social security and I had to make decisions like this, and quote the relevant sections of the Social Security Act, all the time.