Well, BastBlack, it's more like a half-truth wrapped in a joke.  It's a good joke, mind you, but the things left out can be pretty important.

For example, the Mac OS has security holes.  It's just that the people who like to create viruses, worms and other destructive bits of code perfer to get more bang for their buck.  And, since Macs make up such a small percentage of the computers out there, they've been left alone.  That doesn't make them more secure, it just makes them worthy of being ignored ... for now.

I think you all ought to thank your lucky stars and hope that more people don't decide to get a Mac, because if they ever get a real toe-hold, you all are going to be a much more attractive target.

The other half-truth that cracks me up is that PCs are only for business.  There's a sterotype that isn't grounded in reality.  Oh, yes, I am able to use my PC for business, but I've also be publishing photographs, creating books and artwork, playing games, listening to music, for close to 2 decades now.  So, to say that PC users are non-creative business types (which is the stereotype of the ads), is .... well, wrong.

So, it's not "like the truth" wrapped in a joke .... it's not the truth at all.  It's an ad ... and as we all know, ads are not for dissemminating information, they are for selling a product.  In this case, in order for Jobs et al. to sell the Mac, they have to make the PC look bad.  It's a not very noble try ... but it may work, for those people who, as you said, don't want to know anything about their machine and plan to live close to a Mac Store for the rest of their days.

Could be worse, could be raining.