Firstly, they discard the entire idea of justice, instead seeking to curb street racing by punishing the innocent. If a person commits multiple street racing offences, they will punish them by taking someone else's car away and crushing it.
Secondly, it takes a car crusher to human rights, violating the freedoms of movement, association, peaceful assembly, and from unreasonable search and seizure, not to mention the rights to justice and the right against disproportionate punishment - all of which are affirmed in the Bill of Rights Act and in multiple international instruments our government has sworn to uphold.
No-one likes boy racers. They're loud, obnoxious, and a danger to cats. But justice and human rights are indivisible. We need to protect them for everyone, even people we despise, or we have no right to claim those protections ourselves. What the government is doing here is simply wrong, and we should stand up and tell them so.