Ultimately, it is up to the referee to assign colors; however, there is another factor in making that decision which has led to the counterintuitive color selection in this match. In folkstyle wrestling, there are primarily two common types of competition: individual or dual team. In the former type, advancement is based solely on an individual's results, and so colors can be assigned on a match-by-match basis. In dual team competition, however, advancement is based on a series of fourteen matches at all fourteen weight classes (from 106 lb through 285 lb), and so the color selection made before the very first match continues through all fourteen matches. If for some reason a wrestler is wearing a singlet color that is inconsistent with the rest of their team, counterintuitive ankle band color assignment like you see in this video can be the result. As an official, I will also add that while it can be confusing for viewers, just imagine how confusing it can be for the referee who has to signal split-second scoring decisions using colors that are opposite of the singlets. It keeps us on our toes.

As a referee, I don't care what the assigned colors. In this match I'd have had the wrestler in the green singlet as the green wrestler.