It's a case of support released much time after the anime ended. For cases like this they tend to give the lines for the DSOD version of the character, but there is no such thing as a Bandit Keith (DSOD).
They could simply have made the line anyway, since they did that sort of thing for other characters. They did way less voice lines for the first DM characters. They didn't make many lines for countless cards the Yugis used, even.