"Any competition organized by the WDC is completely Open."
Perhaps those organized by the WDC itself, but most "WDC" competitions are organized by its national member bodies, and many of those are not open. You still must hold an appropriate membership card to enter.
You might think they are a bit better than the IDSF in that they don't threaten to revoke your membership card if you dance elsewhere. But that's only true for amateurs and they don't have many amateur events. If you dance in an IDSF pro events, Donnie has threatened to declare you to be an amateur again. WDC does have lots of pro events, so they protect those.
In the end they are both the same - they make threats to protect what they have, and then turn around and claim to be in favor of free choice in the area where they don't yet have much of a presence to loose to "fair" competition.