Actually it is the protestant who makes a claim that contradicts centuries of belief and the clear words of Jesus in Scripture.
You say the Apostles did not believe what the others believed when Jesus made what He Himself called a shocking teaching.
Yet, Scripture does not say that anywhere.
So, that leaves you to prove your opinion.
It’s not opinion. It’s straight from scripture. Here’s a hint.
John 6:63 It is the spirit that quickeneth; the flesh profiteth nothing: the words that I speak unto you, they are spirit, and they are life.
I highlighted it in red for you. “The flesh profiteth nothing”. Yet Catholics insist it is the flesh. Catholics directly contradict what Jesus is saying there. Notice He then says the words He speaks are spirit and they are life. It’s the words He speaks not His flesh that they are to eat.
Here’s another hint.
John 6:67 Then said Jesus unto the twelve, Will ye also go away? 68 Then Simon Peter answered him, Lord, to whom shall we go? thou hast the words of eternal life.
So Jesus says “the flesh profiteth nothing” but Catholics say it’s the flesh that is needed. Peter affirms it’s Jesus words that feed them and give eternal life. In other passages of scripture reference is to eating the word.
Jesus also said.
Matthew 15:17 Do not you yet understand, that whatever enters in at the mouth goes into the belly, and is cast out into the draught?
Here are some scriptural references to illustrate.
Jeremiah 15:16 Thy words were found and I did eat them; and Thy word was unto me the joy and rejoicing of my heart.
Ezekiel 3:1 Moreover he said unto me, Son of man, eat that thou findest; eat this roll, and go speak unto the house of Israel. 2 So I opened my mouth, and he caused me to eat that roll. 3 And he said unto me, Son of man, cause thy belly to eat, and fill thy bowels with this roll that I give thee. Then did I eat it; and it was in my mouth as honey for sweetness. 4 And he said unto me, Son of man, go, get thee unto the house of Israel, and speak with my words unto them.
Deuteronomy 8:3 And he humbled thee, and suffered thee to hunger, and fed thee with manna, which thou knewest not, neither did thy fathers know; that he might make thee know that man doth not live by bread only, but by every word that proceedeth out of the mouth of the LORD doth man live.
The eating of his body and blood are the equivalent of ingesting his sacred instruction.