[Uri’el-2012]

Is Windows inherently more vulnerable to malware attacks than OS X?

Microsoft Windows(dos) was designed for one person.
Hence there was never any understanding of a hostile intent to crack the system.

BSD Unix on the other hand was written under contract
from DoD with a mission to defend against hostile attacks in a multi-user environment

Mac OSX was built on a variant of BSD with an additional twenty plus years of understanding of hostile intent.

When I worked at Bell Labs twenty plus years ago there were posters on the walls of cubicles stating :

4.3 > V

Among the world's best Unix programmers, BSD was always considered better than Unix

[Echo Talon]

Berkeley Software Distribution wow man hippies and stuff...

[Question_Assumptions]

Windows was written before computers were commonly networked to the Internet. And contrary to popular mythology that Microsoft helped the Internet explosion, let's not forget that Microsoft launched MSN as a proprietary network and one needed 3rd party Windows TCP/IP socket software (like Trumpet WinSock) to even connect to TCP/IP networks until Microsoft was dragged kicking and screaming to the conclusion that they couldn't control the Internet and added their own socket support.