"Sold out" refers to the initial offering and marketing initiative and the fact that the resort is no longer part of that initiative. You can still purchase any of the "sold out" resorts because ownership is fluid. Between wait lists, foreclosures, ROFR, etc. DVD can typically obtain inventory at a specific "sold out" resort within a short amount of time. The big exception to that is VGC, which is a completely different situation.
Quite frankly, given the price differential between direct and resale at BLT, I don't understand why anyone would want to make BLT their home resort as a direct purchaser. But that's a conversation for another thread I suppose.