That's brutal. But I really feel for the dude. imo, it looks like he was trying to make sure he hit diggs so he caromed and went down inbounds thus ending the game. It was FG range after all. They above all could not let him get out of bounds.
Of course, the fact Diggs was able to make the catch in the first place is another issue. Oh, the bitter tears that NO shall shed over this game for the next decade.
gotta add an edit: as a long suffering Browns fan, I am going to blame defensive coach. I would wager good money, NO def coach sent in word, sure let them catch, but don't let them then traipse out of bounds to stop clock w/ 2 seconds. I bet that was a coaches call. But of course, Williams also could have hit the hitstick too quick.
edit 2: scratch the above. Diggs was still 3-4 yards inbounds. If Williams' goal was to make sure of an inbounds stop and end of game, he could have just stood underneath him and caught him as he came down and game over. In other words, Williams rangered in and got early aggro and ate the catch and the mob went straight for the healers, err, endzone. what a fuckin game.