I can think of only one reason why idling would be bad and even then a lot of newer cars have features designed to prevent this "risk". Note I don't really know if this is bad for it or not. When idling with the transmission in park, it is most likely not circulating the transmission fluid, it must be in at least neutral or a gear for it to circulate. Right off the top of my head though I can't think of anything that would be bad by doing this.
I know that I don't know enough to be an authority on computer security. As a result, I refrain from posting "advice" based on guesses.
The only time advice should be posted is when it is based on concrete knowledge. Please see dipweed's post above. It is an example of a post that is based on concrete knowledge. -- Striving for Parfection.
Point taken, now go back and re-read my post. I never once said it was "concrete knowledge" and even said I can't think of anything bad that would come from my scenario. I was simply pointing out what the "professional" article writer might have been thinking.