I disagree. I think the way the quiz is set up and the question being asked, "who is the most moral / honest," means that's exactly the sort of information this is teasing out.

The quiz sets up a highly emotionally charged situation that a lot of people are going to make snap judgments about. The first couple of ranking decisions made are going to reflect those snap judgments. The neat thing about the ranking process is that it forces you to think beyond the snap judgments and consider the relative morality of all the characters. It asks you to do this while your guard is down, i.e. if they just asked you the relevant questions about your moral leanings, you wouldn't necessarily give the ones you are really operating on subconsciously.

The other neat thing is the ambiguity of the situation given. You don't know the character's histories, you don't know why the sheriff locked them up, the whole thing is set up so you read those details into the situation. What you read into it will certainly affect your rankings. For example, an unassuming reader won't snap to the judgment that the sheriff forced Maid Marion to have sex with her.

You haven't addressed my concern: you've focused on my judgments about Robin, but my concern is that you can't analyze my opinion about Robin in isolation, because it's only a relative ranking.