Reason wrote:

If Linux had viruses, we would ever know, because Linux-heads would refuse
to acknowledge their existence.

Gibberish - there have been acknowledged Linux worms.  There are two issues though:

Linux is not deployed as widely in a single configuration
The security models used in Linux are stronger than those in Windows

Hence writing a virus for Linux is far more difficult than for windows, and it is not as likely to work on all Linux systems, and there aren't as many linux systems, so it isn't going to spread much...