No one is abusing the trust system, it is only a negative trust and it should not stop you to trade here on bitcointalk.org ; you have only to use always a valid and trusted escrow.
But it actually does. Look at my tag now because Vod gave me one negative trust. Sure you can look at my feedback and see 20-30 people giving me positive trust but sad that one feedback can hurt u that much. How many people would take the time to look at the actual comment left