Jesus already told us why He didn't correct these people...One is that He know they 'already' didn't believe...And the other you'll know when you find out why Jesus spoke in parables...
And I'd say a third reason is to weed out those who refuse to come into the Kingdom of God, the Spiritual Kingdom, who will not and can not understand the Spiritual things of God...
John 6:30 takes place in the synagogue at Capernaum. The Jews asked Jesus what sign he could perform so that they might believe in him. As a challenge, they noted that "our ancestors ate manna in the desert."Paul also said, "Therefore whoever eats the bread and drinks the cup of the Lord unworthily will have to answer for the body and blood of the Lord. . . . For any one who eats and drinks without discerning the body, eats and drinks judgment on himself" (1 Cor. 11:27, 29).
Jesus then told them the real bread from heaven comes from the Father. "Give us this bread always," they said. Jesus replied, "I am the bread of life; whoever comes to me will never hunger, and whoever believes in me will never thirst." At this point the Jews thought, just like many protestants that HE was speaking metaphorically.
He then repeated "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."
The Jews then argued among themselves, saying, How can this man give us his flesh to eat?" (John 6:5152).
His listeners were stunned because now they understood Jesus literallyand correctly. He again repeated his words, but with even greater emphasis, and introduced the statement about drinking his blood: "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" (John 6:5356).
In John 6:60 we read: "Many of his disciples, when they heard it, said, This is a hard saying; who can listen to it?" These were his disciples, people used to his remarkable ways. He warned them not to think of flesh, but spiritually: "It is the Spirit that gives life, the flesh is of no avail; the words that I have spoken to you are spirit and life" (John 6:63; cf. 1 Cor. 2:1214).
But some did not believe."After this, many of his disciples drew back and no longer went about with him" (John 6:66).
Here some followers left Him because of what HE said (perhaps even Judas). If it had all been a misunderstanding, if they erred in taking a metaphor in a literal sense, why didnt he call them back and say 'no, you misunderstood me, I meant a symbol'? Both the Jews, who were suspicious of him, and his disciples, who had accepted everything up to this point, would have remained with him had he said he was speaking only symbolically.
But he did not correct these protesters. Twelve times he said he was the bread that came down from heaven; four times he said they would have "to eat my flesh and drink my blood." John 6 was an extended promise of what would be instituted at the Last Supperand it was a promise that could not be more explicit. Or so it would seem to a Catholic/Orthodox