Apple Leopard insecure?

A firewall that is off by default? No granularity to the user settings?  Sounds like Leopard might not be as secure as people like to band around

We've been making security part of the development methodology for years now and the fruits of our labour are starting to pay off - we had the fewest vulnerabilities of all OS in the first 6 months after launch. 

To find out more about security in Windows Vista read the Windows Vista Security Guide.

My question is, does turning the firewall off by default count as a vulnerability or is it something worse?