The Fumble call

[Earendil]

I think it really came down to there not being enough evidence to overturn it. As others have said, had he been called down by contact, they still wouldn't have overturned it.

As far as anti-Bengals bias goes, I used to think it was a real thing. Then I realized that officiating league wide just sucks. That said, I do believe that certain teams get preferential calls because they are money makers for the league. It's probably not always conscious, but it's still there.