The architecture point is valid
Not wanting to prolong or evoke further shots fired, I will confirm as correct the poster who stated that Linux is secure not via obscurity but by the way the file system is designed. Now, You can't fix stupid...if you send me a script and tell me that it's the winning lottery numbers for next week (and oh please do change the permissions to execute) and I do it, then all the protection in the world isn't going to help me. Here is where the difference in Linux and Windows comes into play. In Windows, most usually, whatever malware or virus/trojan/havoc is in the payload will deploy to the users address book, chat addresses, etc and go forth doing it's dirty work. In Linux, the damage stays local...the way it should be.
The only one harmed is the idiot who opened it.
Why do you think the Battle-Readiness Group for the US Army and most of Wall Street switched to Linux on server and desktop alike? When queried why the BRG wouldn't be renewing their licenses, the Procurement Officer stated it curtly.
"When your computer crashes, you are inconvenienced, when my computers crash, good men die.
That's why the BRG switched to Linux.