This is true, while if those who went away did so because they were repelled by the literal meaning that the bread and wine are really Jesus flesh that was broken/crucified and blood that was shed, then they were not believing like Catholics demand we take Scripture, even though they claim to be taking it plainly literally.
For to take it plainly literally that this flesh they were to eat was what would be crucified for them then it would be manifest as that crucified Christ versus a form that looks, feels, tastes and would scientifically test as bread and wine, yet which really did not exist, being the "real" body and blood of Christ instead, even in every microscopic particle (until the bread and wine that do not exist begin to decay, such as mold evidences). Certainly this palatable form is not what they would be rejecting, but one which Catholics themselves reject.
And here i would like to ask of you or any others (note large ping spread) who are scientifically minded when matter, as in bread, begins to decay, which would exclude this Catholic christ from being in the elements at issue here, and if microscopic particles of such may be airborne, such as the wine evaporating, which would place this Catholic christ various places).
And as a lawyer, could one be charged with stealing a consecrated host if the plaintiff considers the host to be a real spiritual entity, and that what was stolen really does not physically exist?
And that analogy is given, in verse 35: And Jesus said to them, "I am the bread of life. He who comes to Me shall never hunger, and he who believes in Me shall never thirst. (John 6:35)
That can easily be rationalized by Caths as meaning spiritual hunger and thirst by physically consuming non-existent bread and wine that is the "real" body and blood of Christ.
Instead, the analogy that helps us understand what He is saying is Jn. 6:57:
As the living Father hath sent me, and I live by the Father: so he that eateth me, even he shall live by me. (John 6:57)
As how the Lord Jesus "lived" is analogous to how we are to live, then we must find out how the Lord Jesus lived, and thus, as with the other uses of metaphorical language in John , we must look to other statements, in which we see that
But he answered and said, It is written, Man shall not live by bread alone, but by every word that proceedeth out of the mouth of God. (Matthew 4:4)
And therefore, using metaphor once again in John, (which is done at least 5 times before Jn. 6), the Lord stated,
But he said unto them, I have meat to eat that ye know not of. Therefore said the disciples one to another, Hath any man brought him ought to eat? Jesus saith unto them, My meat is to do the will of him that sent me, and to finish his work. (John 4:32-34)
And which perfectly corresponds to the Lord's explanatory words at the end of the John 6 discourse,
What and if ye shall see the Son of man ascend up where he was before [thus not being around to give His physical flesh]? It is the spirit that quickeneth; the flesh profiteth nothing [consuming physical flesh nowhere in Scripture provided spiritual life]: the words that I speak unto you, they are spirit, and they are life. (John 6:62-63)
And which also corresponds to the theme in John of contrasting the physical with the spiritual, and of believing being how one obtains spiritual life, and which metaphorical understanding of Jn. 6 alone easily conflates with the rest of Scripture.
To God be the glory.
Amen!