Sorry but this was a blatant missed call. There's no way you are going to convince me that this was an acceptable no-call. Somebody on the Bengals sideline is pointing it out right after it happened, that might be the head coach. The gunner was clearly outrunning both of the Chiefs trying to block him, and the one takes him out with a shove from behind. And arguably the other guy is holding him with that one arm:
By knocking him down, it allowed them to get out in front to block him after the gunner got back up, and that created the path to the sideline for Moore. It was a very significant missed call.