Apparently you have a lot of "why" questions. Questions that you think would make a metaphor to be not a metaphor. Let me try to help you with that.
<<<why did angry arguments breakout over this?>>>
They were really there for food for the stomach(26), and Jesus rebuked them for that (27). Then He pointed to Himself, that they should eat Him. Now, what do you think that sounds (in the literal) like to them? So, they murmured among themselves. For that simply is madness to their hearing.
<<<why did the Jews take Jesus’ words literally and say, “How can this man give us his flesh to eat?”>>>
They did, and that was the problem. That was why they murmured among themselves and quarreled over such foolishness and madness saying "How can this Man give us His flesh to eat?”(52)
<<<why did Jesus then give an “ultimatum” after the disciples argued over his teaching? “Amen, amen, I say to you, unless you eat the flesh of the Son of Man and drink his blood, you do not have life within you.”>>>
That wasn't an ultimatum sir. Jesus in v.53-58 just continued what He was telling them about Himself. Of course He was not telling them that they kill Him there and then and that they all eat His flesh and drink His blood for them to have eternal life and not die. Perhaps, if you and five thousand more, who takes the words of Jesus there literally, would have killed Him and ate Him, for then you would not die and even have eternal life or would you, like them, argue over His words?
<<<why did Jesus say his flesh is “true” food and his blood is “true” drink?>>>
It was a figure of speech He used to tell them about Himself. He used this figure of Him being the "bread of life" as they followed Him seeking for food.
<<<why did the disciples say, “this saying is hard, who can accept it?”>>>
They did not realize that what Jesus was telling them is figurative rather than literal.
<<<why did Jesus say, “does this shock you?” >>>
Because Jesus know they are shocked for they murmur and quarrel about what they heard Him say about eating His flesh and drinking His blood, that they did not understand what He was telling them.
<<<why did many of his disciples return to their former way of living and no longer accompany him?>>>
They did not understand what Jesus was telling them (v.60). If what Jesus said was literal and not figurative, then they would not have complained and said "This is a hard saying; who can understand it?". For then, they would have understood Jesus, since there is nothing hard in what Jesus said if taken literally. It would not be a hard saying. What is hard for them, since they took it literally, is HOW can Jesus give them His flesh to eat (52). To them, that is simply impossible, if not, madness. So, perhaps they thought that Jesus had gone mad and crazy. If they continue to follow a man whom they thought to be like that, what would that make of them?
<<<why did Jesus ask if the twelve apostles were going to leave too? >>>
Jesus simply wanted to know from them if they too would do as they did, if they too think of Him as they did.
I hope this helps.
Tong
R1304
The crowd doesn’t initially take Jesus’ comments to literally. He has to use this literal imagery three separate times before they finally take it literally.
The First time, In John 6:32-33, Jesus says: “Truly, truly, I say to you, it was not Moses who gave you the bread from heaven; my Father gives you the true bread from heaven. For the bread of God is that which comes down from heaven, and gives life to the world.”
The people think that He is referring to literal bread, but they don’t think that He’s referring to Himself. Their response is (John 6:34), “Lord, give us this bread always.”
So He approaches it
a second time, explaining that He’s referring to
Himself. This culminates in John 6:41, in which He says, “I am the Bread which came down from Heaven.”
The crowd still doesn’t take Him to literally mean that His Flesh is Bread. They take the saying figuratively, and their shock is instead at the implication that He is saying that He came from Heaven. They say (John 6:42) “Is not this Jesus, the son of Joseph, whose father and mother we know? How does he now say, ‘I have come down from Heaven’?” Notice that in the way that they have reframed it, they’ve disregarded the “Bread” reference entirely, assuming it to be metaphorical.
So Jesus addresses it
a third time. This time, He emphasizes the explicitly Eucharistic aspect, in a way that is virtually unavoidable (John 6:48-51):
I am the bread of life. Your fathers ate the manna in the wilderness, and they died. This is the bread which comes down from heaven, that a man may eat of it and not die. I am the living bread which came down from heaven; if any one eats of this bread, he will live for ever; and the bread which I shall give for the life of the world is my flesh.
It’s only
at this point that they take Him literally, after He’s presented the same teaching three different ways.
So that’s the first difference. Here, you don’t just have some naive overly-literal crowd assuming that Jesus must mean everything literally. You have Jesus hammering this point over and over until the people finally take Him at His word. The second difference is how He responds to them taking Him literally.
And He
does clarify His meaning, but He does so by
doubling down on the literalism (John 6:53-58):
Truly, truly, I say to you, unless you eat the flesh of the Son of man and drink his blood, you have no life in you; he who eats my flesh and drinks my blood has eternal life, and I will raise him up at the last day. For my flesh is food indeed, and my blood is drink indeed. He who eats my flesh and drinks my blood abides in me, and I in him. As the living Father sent me, and I live because of the Father, so he who eats me will live because of me. This is the bread which came down from heaven, not such as the fathers ate and died; he who eats this bread will live for ever.
His language is even more strongly literal
after He’s challenged on than before. It’s 180 degrees opposed to how He responds in every instance in which He’s using figurative language
This becomes even clearer in the verses following. After Jesus has emphasized (for
the fourth time now) that He means this literally, His disciples say, “This is a hard saying; who can listen to it?” (John 6:60). Jesus then presses them on it
again, and John 6:66 says that “After this many of his disciples drew back and no longer went about with him.” Then, Jesus confronts the Twelve, and
presses them on it (John 6:67): “Will you also go away?”
THIS IS NOT METAPHORICAL AT ALL!!!