I believe that in Expanded, Battle Compressor's existence allowed the first three of the cards in question to run amok in Expanded until this point when the decision was made... As for Shaymin-EX, the fourth card, Crobat V & Dedenne-GX's once-per turn allowance vs. Shaymin-EX's scoop-and-reuse allowance could have outdated that card. FYI, Scoop-Up Net is not the only scoop card in Expanded. Remember Super Scoop Up? As long as there's more than one option to scoop up Shaymin-EX out of play and back in again, banning the net won't eliminate the possibility completely, so to eliminate such scenario, either one of these two things had to be done: Shaymin-EX getting banned, or an errata getting issued to limit all draw abilities to one time per turn, regardless of off-and-on shenanigans. And they chose to do the former of the aforementioned things to eliminate multiple-times-in-one-turn draw...