I'm skeptical that the B&W e98s were simply soaked and all the colors were removed from them, yet the blacks and greys, as well as all the ink on the back were untouched. I do remember Steve's orange e98 Young which lost a lot of color. If I remember the story, I believe he forgot about it and left it soaking for 3 days. However, the card still had some color to it that was quite visible, just very faded. Some of the e98s I've seen have had no color at all.
Also, some of those e98s were in numerical holders. If evidence of soaking could be determined under a blacklight or otherwise by SGC, it would seem to me that they would put the card in an "AUT" holder.
Many of the e98s I saw, such as the Mack from the original post, had very crude cuts to them which also leads me to think that they could have been cards that missed color passes or otherwise became printer's scrap, and then taken home and cut up by hand. Ignoring the color on the cards for a second, the cuts alone are indicitive of cards that never made it through the entire printing process and were pulled early for one reason or another.
Another thing, if I recall, a lot of those e98s were also really dirty. So the soaking removed all the color but left the dirt?
All that being said, I do believe that soaking is a good theory for what happened to these e98s and it's clear to me that soaking does cause the loss of a significant amount of color. Just wish there was a way to test this without needing to call on one of my e98s to be the "sacrificial lamb".