The fact that you would place any blame on another defender is all that matters, it was 100% on Young. Yes, Matic should have done better but midfielders often miss interceptions and you expect your fullback to stay tight and not have his blood twisted twice by very average footballers.
As I say both goals are 100% on Young, if he simply does his job as a fullback, they score neither. If it's on Shaw's side, they score neither.
You are scapegoating Young for the goals and even use Shaw as an excuse to blame Young, I can see clearly because you hate him. To be fair, there are other players that also deserves to be mentioned for the goals and should take the share of the blame. Both goals clearly are not a single individual's fault.
You failed to identify what Matic did wrong. It's not about him failing to intercept the ball, Matic didn't mark his man during the throw in, it's the most basic thing in football. Young wouldn't need to be in one on one situation with Kenedy from the first place if Matic mark his man during the throw in.
Bailly was supposed to be in a good position to intercept the the pass but he did nothing, as a centre back he looked like headless chicken in that situation, unable to read the game well.
You think Young isn't doing his job as full back, then the same can be said to Matic didn't do his job during the throw in, and Bailly didn't do his job as centre back.
Don't let me get started with 2nd goal, Pogba didn't close down the crosser, Young got beaten and Bailly once again prove his ability not able to heading the ball.