I guess you are seeing the rating depending on your personal trust setting. It's different for sure for others. i.e I see green for BayAreaCoins, OgNasty, TMAN.
mprep is the same for me...
Astargath is talking about DefaultTrust settings, which means that this is applicable in a grand scheme.
Retaliatory feedback is inevitable. However. the part that works is when others jump in to give their opinion about certain sent feedback. If other DT members disagreed with BAC's rating, they could easily send mprep positive feedback to counter the rating.
In the second case about Lauda, there must be a clear distinction made between trust feedback and trust lists. Lauda receiving negative trust from DT members does not mean that they will be excluded from DT.
Rather, for an exclusion to happen, the number of DT1 members that have ~Lauda (an exclusion) in their trust list must exceed the number that have Lauda (an inclusion) in their trust list.
In the third case, if it is justified there is often need to leave multiple feedback. To delete earlier feedback and "edit it in" to a later feedback seems unconstructive.
I know getting a negative rating does not mean you get excluded from DT, im not new here. It just seems counterproductive to have DT members with negative ratings from other DT members. If they can't trust each other why should we?
It seems that on mprep case almost no one really wanted to say anything because of fear.