Here's how it works:

When someone scams another person, the victim can make themselves feel better by leaving the scammer Negative trust.

That forces the scammer to make or buy a new account for their next scam.  It's harsh, but fair.

To better their scamming abilities, creative scammers can make multiple accounts and give themselves Positive trust.

This is all highly ironic because if a reliable trust system was possible, we wouldn't need Bitcoin (which ingeniously replaced the unworkable, Byzantine trust schemes with proof of work).