You're not an idiot. If you look at things from a grand perspective, it is the fault of big companies who have opened up these flaws due to their greed, they are the "root idiot" if you will.
To which faults are you referring to?
I believe that when you are using a proprietary operating system like Windows or Mac OS X, then you should be absolutely protected to the fullest extent and you should not have to even have the slightest bit of worry.
You can't, because there is no such thing as 100% protection, literally. You should worry when using a computer that is connected to the Internet, and that's why you should take the necessary precautions. You're responsible for your security.
Unfortunately though, we don't live in a world where companies care about consumers
Plain false. If companies don't care about consumers, why are consumers picking them anyway? Companies that are careless with the user experience, go out of business. The fact that most consumers don't care about security or privacy is the root of evil. Companies only follow demand.