That's a good idea Joe. We should require criminals to ask permission before cutting the wires to the burglar alarm so they can break in your house. Linux IS much more secure by design, and its dominance in areas like web servers means that installations are often looked after by more professional and aware users and vulnerabilities are detected and fixed much faster. Also, the fact that modern Linux desktop installations are designed to discourage users from logging in as superuser/ administrator helps greatly. But there are Linux viruses, exploiting bugs or weak design in areas of the operating system (it's designed by humans), it's mainly the richer pickings to be had from the massively more vulnerable Windows population that means you can live quite happily without a Linux virus checker.