Whaleeyeman: Perhaps; I'm more comparing two people who may say they are passionate, but have different ideas of what that entails. For example, one person may consider reading a lot of books to be passionate, whereas someone else may think that trying to figure out the correct idea in a book before looking at what the book says to be passionate.
Because the whole thing is ambiguous, my point is that it's hard to go by purely what people say about themselves to determine how dedicated they truly are to the game.
So when someone says "You have to have the right attitude rather than talent," and people disagree with it by pointing out counterexamples, it might be because people have different definitions of "right attitude." Someone who is willing to read lots of chess books still doesn't, fully, have the right attitude in my opinion, because when you read books, you are not necessarily thinking about the game, but passively looking at someone else's idea.