It's a problem I've had since I was wee lad. I want to understand, truly I do.
Now about that rulebook...
From the ref on the field...
"The ruling on the field is that the runner did not complete the catch during the process of the catch".
I'll ask you again, what don't you understand about that explanation?
ETA: From the same ref, after the game...
Q: What is the rule used on the near Detroit touchdown at the end of the game?
Steratore: The ruling is that in order for the catch to be completed he has got to maintain possession of the ball throughout the entire process of the catch.
Q: He was on his behind before he rolled over. If he stayed on his behind would it have been a touchdown?
Steratore: No. We don’t play with the two feet or one knee or anything of that scenario. We’re talking now about the process of the catch. He’s catching the football, as he goes to the ground, he must maintain possession of the ball throughout the entire process. So as he continues to fall if he fell with two feet and his elbow hit the ground and came out it would be incomplete.
Q: It looked like he had the ball up in one hand while on his rear end, but there was continuation?
Steratore: Well, the process was not finished until he finished that roll and the entire process of that catch.
Q: How long did it take to determine that?
Steratore: We had the normal time [one minute] as far as the video was concerned. We would not run it any longer