It was some of his disciples, why didn't he correct them? I know what He said is hard saying, but if it was all metaphor why did He ask who was left if they took offense at it and if they too would go away? Peter said they wouldn't go and still Jesus did not correct them. His Flesh is food indeed and His Blood is drink indeed. You say it is all metaphor but why, do you not believe that Christ is capable of such an act? Or that it would be usless for our salvation?
Read the Chapter again Pelayo, and break it down. Look at the way he states the argument each time. He goes from the blatent to the metaphor and the metaphor is what trips them up. The Jews didn't understand but the disciples understood fullwell that the whole time he was saying "Hey, You have to believe in me to be saved". The Disciples that left were with him and yet didn't believe, just as Judas didn't. If they'd seen all he'd wrought, heard all he'd said up to then and still didn't believe, they weren't going to. He was already going to die for them; what more do you want, him to tackle them at sword point and say convert or die? That isn't the way the Lord works. Our faith and our choice - not his. He'd just said his peace and explained it several times - they already understood. And the understanding of the statement ticked them off. You might as well say the figured him for a quack or a blasphemer.
Jesus is capable of anything. But capability and usefulness combined with action are not there. Belief in the Lord and the acceptance of the sacrifice is our salvation. You want that to be it, then you also want communion to be it, and baptism...... No, that isn't how it works. The belief as Jesus says over and over all through the Gospels is the only way. The Only way - period. He made no exceptions. Communion is a rememberance. And Baptism is a command. Salvation is gained only by confession of faith in Jesus. One gate, one path - long and narrow. And few find it. Not because it is hard to see; but, because people will not heed the word or the Lord.
There is more I can say; but, if you don't get this, you won't get the rest either.