The actual Special Editions (the 97 theatrical releases are really the only ones that are actually “Special Editions,” everything else is just Star Wars) seemed a lot more concerned with “fixing” things, and a lot of errors were tackled. The Special Editions were also on Fox’s dime, entirely. Some of the more egregious additions to the Special Editions were done as a sort of testing ground for prequel effects, but the SEs did do a decent job of removing “mistakes” from the original releases.

You’re right however that the 2004 DVD release and the 2011 blu-ray release (which were Lucasfilm budgeted, I believe) were less about fixing anything and more about adding stuff if they could. Those releases didn’t really have the same mandate as the Special Edition did, and likely had a smaller budget. So the idea there was different, and the execution reflects that - those releases are definitely more along the lines of “put that thing in there, that’ll be cool” instead of “here’s a list of errors I’d like cleaned up.”