It seems like assumptions are being made without enough info.
It looks to me like the C slid over and the guard slid over but Massie did not. However, we don't know the line call. It could have just as easily been the G's job to drop back and pick up the outside blitzer.
Either way, I'm pretty sure they didn't draft Humphries based on this play.
At some point, I'll build the technical know-how to figure out how to convert these to animated gifs. That day is not today.
Some plays are designed to allow a free rusher. The QB's job is to account for that. Fanaika has to account for the DT lined up at his outside shoulder first; Massie has to account for the DE alinged at his outside shoulder first.
After the snap, the DT crosses the OG's face and Fanaika engages with him and hands him off to Sendlein. The DE goes straight up the field in parallel with Barron. Massie engages him and blocks him until Fanaika comes over to help out. They combo block on him, at which point Carson has enough time to move into the empty space between the guard and tackle or get rid of the ball.
Overall, I agree that we didn't draft D.J. Humphries because of this play.