Q: Exactly what are we trying to protect? It has a lot to do with our culture and the fact that they named rogue programs viruses.
As a practicing tech support guy I can give you real world examples as to why you should care and worry:
Scenario One: Imagine it is 11:50 pm, you just finished typing up a paper for this class that was 16 pages in the APA format. Now imagine that you have saved your document, only to realize that your document has just been deleted by a virus and the virus flashed the BIOS of your motherboard, and the firmware on the hard drive with corrupted data. Now not only have you lost your document that can not be replaced but your motherboard has been permanently be destroyed as well as the hard drive.
Scenario Two: A simple spyware program gets on to your pc via a popup and steals your bank account and credit card info. You monthly statement comes with a 100 or more monthly statements from other credit cards companies that you did not setup accounts yourself and now your owe $100,000 in debt legally.
Everyone needs to take defensive measures for safe computing. Otherwise you may find yourself at the wrong end of someone else's evil.
Q: To answer the question posed, we should blame Microsoft for all of the viruses. If they hadn't gone around making people angry, these mad computer scientists would never have created these things.
Blaming Microsoft for all the viruses is like blaming god who created us for all our problems. Individual people are the responsible ones not Microsoft. If someone takes a butter knife and kills someone, is the person that did the killing or the butter knifes manufactures fault.
If you read the department of homelands security's web site you will see that there are just as many holes and security issues with Linux and a ton of others software and devices.
As for the mad computer scientist his motive is profit and there is no profit in a virus. It is a well known documented fact that the vast majority of viruses are written by teens with virus writing tool kits freely available for download. The guys are known as script kiddies.
Don't get me wrong, I am not defending Microsoft, as there IS a lot they could do to help curb the issues too.