I've also interacted with him via email and was put off by his response but after reading some of his blog posts I think this is how he gets stuff done with limited resources. The email was short and to the point, which feels "rude", but it gave me exactly what I needed in a few short words.

Steve Jobs is famous for his very short emails and I suspect they evoked similar responses from people.

I like to give more detail in my own correspondence, but it does take significant time.