First:
I recall you saying you've never seen the actual post where it was said this would be gone, well here it is.
Second, there's no way TOs these days will risk lower attendance, or backlash after the fact, due to allowing something that is perceived by many to be a broken character/variation at their tournament. It's just not the smart thing to do. This game is early and perceptions are important. If people go to these early tournaments and get beaten by a Spectral Ermac who understands how to take advantage of this glitch, there would undoubtedly be backlash. This isn't like the old days, there's more and more money on the line, and people would be that much more upset if they were taken out by something like Spectral Ermac. There are problems with testing these things out at locals too. Just to start people would not take people's experiences facing a Spectral Ermac seriously if they aren't a top player, or were facing a top player, or both. If a few "unknown" Spectral Ermac players joined a local and none of them even make it to top 8, then there would be people arguing that those players didn't know how to exploit the glitch, so their experience wasn't valid. If a pro player went to a local and destroyed everybody with Spectral Ermac, then it would be attributed to a lack of matchup experience and the pro playing at a higher level than everyone else. It'd only be when a lot of well known players played in the same tournament that people would take the experience seriously, and by the time that happens a lot of people may have already dropped the game because of Ermac's perceived nonsense.
Instead of potentially facing any of these worst case scenarios, it would be better to just keep the ban going until the glitch is removed.
(Just to clarify, I've seen your stream where you analyzed Spectral Ermac's options, and agree with you that besides the meter, he doesn't have much, but I'm trying to explain why I think it would hurt the community and the game's tournament scene if Spectral Ermac was allowed)