I believe that the wiggle room comes from Rob Feinstein having the distribution rights to those shows in advance of Heyman selling the master tapes to Vince. So he can still distribute ones that were negotiated at the time, in the same way ESPN has the broadcast rights for a bunch of AWA shows that WWE also owns. It only matters what the agreement was at the time.
I've recently been buying the RF Video versions of ECW events from Highspots and I got thinking, don't WWE own the rights to ECW now? Are Highspots still legally allowed to sell these DVDs, or is it just a whole massive gray area?