I think it is not that as easy as you said. I have Lauda in my trust list while Lauda gave me a wrong feedback. Due to Lauda's feedback sending history which is good for everyone and for me too while trading, I did not remove Lauda from my trust list.
It's not supposed to be easy. If it was easy then perhaps theymos could replace DT1 with 100 lines of PHP code and be done with it.
It's not just about questionable feedback but also how users handle questions and disputes. Everyone makes mistakes and I don't see anything wrong with admitting and correcting an occasional mistake.