I think the headline implies that a hacker/security professional is more likely to have something like prey installed than, say, someone like my non-technical mom.
Honestly, I see your point, and both sides. I've just met a few people that have a similar service installed onto their phones, and I certainly would not call them hackers. Similarly, if someone told me they had this installed on their computer, I wouldn't think, "Oh, cool! S/he's a hacker!" On the other hand, if I saw someone starting "Learn Python the Hard Way" I _would_ think, "Oh shit, s/he's becoming a hacker!". Anyway, I don't really care too much. You do make a good point though. In general, a hacker might be more likely to aggressively try to track you down :)