Need to go back and watch Jon from the beginning of the play. I'm not convinced he saw the ball the entire play.
I think (devil's advocate) that he may have thought it was a "loose ball" in the sense that it was touched, after the block (ie, bounced off someone)
Additional concern
Players (defense) are, generically, taught to always dive onto the loose ball (vs scoop it up) regardless if they think the ball was incomplete or blown dead. I think he just saw the ball, didn't know all the info we did from press box, and tried to just secure it in a bad weather game. It's not like he fumbled trying to scoop and run it. It's not as "dumb" as picking it up and running to the wrong end zone (I've seen this on loose balls before).
Yes it was "dumb" but it was understandable. The funny thing is, if he would have secured the ball, I doubt a single person would be screaming about him "being an idiot" for diving on it there. It would have been, just "a play" nothing more...furthering my point that it's not as dumb as things I've seen before.
A play like Ian refusing to throw the ball to an open Kmet is way more embarrassing imo.