I may be wrong on this, but syndication rights aren't dependent on the original network. In this particular case, Touchstone Television (owned by Disney), produced the show. When it went into syndication, Buena Vista Television (also owned by Disney) distributed the show to stations. In 1996, Disney bought ABC, later (in 2007) changing the name of Buena Vista Television to Disney-ABC Domestic Television. Incidentally, ABC co-owned/s Lifetime.
It is so nice seeing the show without cuts and weird commercial break inserts. I'm watching relatively slowly rather than binge-watching, so I'll have to wait to see if they include the entire discussion on getting rid of their microwave oven during the episode when Blanche gets a pacemaker.