"Stuxnet then hides itself in the PLC"
"Stuxnet then hides itself in the PLC"
Not exactly it doesn't. Maybe you didn't type what you meant. Maybe you didn't understand. Go back to Langner's work and read it again.
http://www.langner.com/en/index.htm
The Stuxnet payload hides itself in the PLC programming tools on the host PC, and corrupts the program which is downloaded from PC to PLC. It's not really "hidden" at that stage, but if you don't look for it you don't see it.
"all of this is is just an avenue to get it to the one or few PC's that are connected to a particular subset of PLCs."
Now we're talking. With most viruses to date, the aim of the malware has been to knacker the PC, or to get info off the PC or money off its user.
With Stuxnet, it seems like the Window box vulnerabilities are simply a delivery mechanism. The actual payload is intended to do something unwanted to a non-Windows box - the PLC. Again, Langner has the details.
"to see what stuxnet is really aiming to do."
To do that properly you'd have to know what program was meant to be in the target PLC. Not many people have access to that information. Langner makes some educated guesses.
The bigger message here is that there is now no valid reason not to ditch Windows as a platform for stuff that can control critical real world kit. That applies as much to Windows for Warships as it does to tools used to develop and manage aircraft control systems or electricity generation/distribution or whatever.
PHBs wake up, you have nothing to lose but your MCP certifications.