Filming a vehicle crash where no humans involved would be of little interest or reason to create such a law on its own merits, which suggests two intersecting motivations (knowing nothing about how this came to be):
1. Drivers are filming crashes and causing further crashes due to being distracted drivers.
2. Human beings are considered to have an automatic right to privacy in scenarios lacking a compelling public interest.
Speaking to one reason only would not weaken the need for the law, so take care to consider the wider concerns beyond just privacy rights alone.
Technically, if human privacy rights are legally enforced in the country where this law exists (unlike the United States), then the existing privacy law could be considered sufficient for #2. But having it on the books makes the judgement call much easier for the general (non-press, non-authority) public, and it also provides a clear warning about crash porn taken by first responders who find fascination with that sort of thing.
All around, it seems a healthy enough law given the context of their country’s human privacy rights. I imagine the press will find cause to argue the edges of it, but I’m hard pressed to come up with any significant benefit to the general public that is being set aside. Identifying such a benefit would be key to arguing that this oversteps.