Well, that's how I see the "do what you love," argument manifesting here. The things that define your true passions aren't going to be the dreams that you dreamed as a child, or as a teenager. You are always developing as an individual, and the things that you love are capable of redefining themselves. One thing that I hear time and time again is that "X" is fun until you have to do it for a living; that's not doing what you love, that's clinging to a bad mistake. You can do what you love by finding something you enjoy and by applying love, there's no mystical "true love" of careers that is imposed from on high.
Hmm, what I just wrote was properly glib, wasn't it?