Lucas forced everyone's hand by putting new additions on the DVD releases and again for the Blu-ray, the latter of which was where we got the infamous "NOOO!" from Vader at the end of ROTJ. That almost overtook the CGI Jabba's Palace performance as my personal worst addition to the movies. Really Return of the Jedi is the movie I take most issue with what was added in. The only improvement I can think of is the John Williams score at the end replacing "Yub Nub". Sorry but I prefer that to an Ewok song closing out the OT.
I'm at least glad I still have my original version DVDs that were released in 2006 but I really don't see any harm at all in Disney putting them on Disney+. I'm certain that Lucas put it in the contract that the original pre-Special Edition OT was never to see the light of day again when Disney bought Lucasfilm.