As long as the feedback sender is not in the DT network, their trust feedback does not have any value....
Wrong. It has value to the person who left it. It serves as a reminder.
The trust system might be borked, but it does have value.
Yes, it has value like masturbation. The untrusted person can give a 1000's negative trust if that might have value then DT will go down by a single minute. Because DT receives maximum negative trust from Untrusted person(non dt).