Just wanted to say that your argument holds true to quite an extent in my case. I also agree with the "practical vs. academic" argument.
I love development with the latest tools and technologies and I easily recognize the top Developmentor trainers and Don Box. 😉 I easily relate COM+ with Don Box, and XML with Aaron Skonnard. I never got to the point where I looked into historical VB figures, though. It's probably because to me, development is a practical passion. I don't enjoy Computer Science-type stuff so I rarely approach it in an academic manner.
My passion in history, on the other hand, is very academic. I dig into sources from 10th century East Asia that nobody cares about. I easily recognize the top 5 scholars in this field. I easily identify the famous rulers and officials at the time.
I identify passion with an act of digging deeply into stuff and get this strange feeling of joy as I learn more and more. To me, passion also directly relates to my performance/achievement in the field. For those fields that I have some interests but don't do well (and I am aware that it's not because of my lack of training) or don't feel as much joy from learning, I simply identify it as "interest".