This has been argument since viruses became well known, they've Turing complete since the beginning:
"Much like an infection, a well-intended but badly designed program to stop viruses can run amok, knocking out thousands of computers or destroying vast amounts of data. Indeed, one program intended to defeat a known virus has destroyed data on personal computers used by businesses and the Government in the United States."
"Much like an infection, a well-intended but badly designed program to stop viruses can run amok, knocking out thousands of computers or destroying vast amounts of data. Indeed, one program intended to defeat a known virus has destroyed data on personal computers used by businesses and the Government in the United States."
http://www.nytimes.com/1989/10/07/business/computer-virus-cu...