I should probably clarify: it's not an entirely bs wall, but it's still a very significantly more dense wave than what SG will throw on average. A wave of this density isn't as much of a problem for the other final cards, because they all follow some very readable pattern that, if understood well enough, will result in you pulling out some muscle-memorized motion to get you through that dense wall. SG doesn't follow such a readable pattern, and so if something like this comes up, you have to decide how to dodge it on the fly. You have a small moment to find that random hole in that random wave and fit yourself through it.
Maybe the wave I pulled from GIL's run isn't the best example out there to say that SG can be luck-garbage at times, but let me put it this way. If I took random screenshots of SG, I might get something like that, I might get something nicer, or I might get something that is pure unarguable batshit. If I took random screenshots of any other final card, they would tend to look about the same (provided you don't try comparing screenshots of, say, LFO when it starts versus when it ends, or Hourai Jewel with someone using clean streaming versus someone who's flying around like Aya on speed).
Also, don't think that I'm using this to say that SG is a bs card and that I hate it like someone who beat my dog to death. It's a legitimate final test of your skill to see if you're worthy of clearing EoSD, and I have nothing against it. But to say that absolutely zero luck factor is involved is what I'm debating against.