So, it isn't just their thumbs, their hands are all over the system. I assume by "thumb on the scale" you mean, "intentionally biased."
I'm not sure Bamacoug was suggesting they are intentionally biased. But he does suggest the algorithm, which they created, for one reason or another is poorly constructed because it seems biased against the Big 12 who has consistently outperformed the system this bowl season.
On the other hand, the ACC has underperformed and they are still outranking BYU across the board. Seems the FPI has overranked the ACC and underranked the Big 12 for some reason. He wants to know the algorithm to ferret out why this gap exists.