Plus, if USD Duels aren't supported then every non-toribash duel related instance should also not be supported. People duel for CSGO Skins and other things just as often.
They aren't. We provide support for items and toricredits being dueled, and we give bans for art-related duels. Any other scam report is disregarded as per rule one of our dueling policies.
Where that misconception came from is beyond me—it's specifically stated in our guidelines what we do and don't support.