Reasons why I or many rational persons wouldn't trade with someone:
- Trolling - I wouldn't attempt to trade with a known troll due to non-trade related deceptive behavior.
- Dishonesty/hypocrisy - Who would?
- General deceptive behavior.
- Many, many more..
According to his own statement, all of these are valid use of the ratings.
I think there is a difference between a "valid" use, and use appropriate for DefaultTrust. I'm pretty sure you can red-trust someone for disliking lemons and stretch the interpretation of "high risk" to mean that dislike of a fruit makes trading said fruits with the person "high-risk". I would argue that this kind of rating is useless and possibly harmful for DefaultTrust, or at least for my own trust network, which is what really matters.
I think these overstretched interpretations of the effects of hypocrisy, trolling, etc on trading are not useful for my trust network and amount to using trust ratings against opinions. Others may think differently, the balance will determine how DT looks like, and I know better than trying to change your mind so this is a good opportunity to agree to disagree.