I think this is probably a discussion the community should have, and you'll notice that my username isn't in any of OP's quoted lists.  That's because while I appreciate JollyGood's attempts to fight scammers and general scumbags, he's far too overzealous with the negative feedback he leaves, and quite a few of the negs he's left have been abusive.  I haven't looked at any that he might have changed to neutral since I excluded him from my trust list, but he definitely has a habit of abusing the trust system with wrongly-given negatives.

So no, I don't think he should be on DT unless he starts abiding by the community standards (and Theymos's suggestions) with regard to what behavior deserves a negative trust and what doesn't.