Did you even read the links you posted? The lupper was patched years ago. Same for XMLRPC. See this link here: http://www.securityfocus.com/bid/14088/solution.
One of your great links is just a forum of people who say Linux is vulnerable. No documentation of any virus.
Also, these threats hardly count as virii. They are injection attacks on the web server. Most desktop users are not even running a web server. They don't infect OS files, just PHP scripts. If we count PHP injection as virii, then Windows has thousands more vulnerabilities to include.
Lots of the virii noted for Linux are proof of concept code that have never been seen in the wild and only the anti-virus companies seem to have any knowledge of it at all. Maybe because it is in their best interest to find Linux virii. And to spread these virii requires an unsecured system and a priveleged user to run the infected program.
There are plenty of Windows virii that do not require a privileged user to run the virus code. Any user can just connect to a website with code that can infect Windows.
You may be too young to remember, but there are virii for MS that you just have to stick an infected floppy in your drive and it will infect the system all by itself. No program needs to be executed by the user at all.
"Take that, you hostile sons-of-bitches!" -- James Coburn, in the finale of _The_President's_Analyst_