There seem to be a lot of people on both campaigns that have negative trust. I'm sure some of it is real negative trust, but for others they may have just gotten spammed negative trust by a disgruntled user here. That is the bummer about the trust system not being moderated (someone can just bomb your profile with negative trust)
Well, it's not that easy... first you need to acquire positive trust, only then will giving negative trust to someone have any real effect (though your trust feedback will still be visible if someone bothers to check it on the affected profile).
EDIT: then again, looking at his trust details, I seem to be missing something as there is negative trust feedback left on his profile from people with positive trust that are under "Untrusted feedback".