There is not now, nor was there when He said a lack of understanding of what He was saying. Had there been, Jesus would have corrected that gross misunderstanding when so many walked away from Him.
He didn’t, because those who left didn’t lack understanding. What they lacked, which the Apostles had, was faith that Jesus is the Son of God, the Christ, and trust in what He said.
“Unless you eat of the flesh of the Son of Man and drink of His blood, you shall not have life within you.”
“For my flesh is true food, and my blood is true drink.”
“Does this shock you?”
“Master, to whom shall we go? You have the words of eternal life.”
Wrong. HE knew what was in them and they had NO KNOWLEDGE of who HE was for they were worldly and they had NO DESIRE to learn either. They were UNTEACHABLE! Jesus didn't force anyone to stay as HIS teachings were sufficient and those who were drawn to Him/TRUTH stayed. Those who were drawn to evil, left HIM.
Anyone who defends the indefensible is not seeking after JESUS! No one can't serve two masters.
God's WORD is the FINAL AUTHORITY and He will turn away from those on judgement day, also, who don't understand that because they 'chose' not to KNOW HIM. God made HIMSELF KNOWABLE through HIS Holy Spirit inspired WORD ALONE. They 'chose' to listen and obey 'another' - the 'deceiver' so they have no one to blame but themselves.
JESUS is The Way, The Truth, The LIFE eternal. Jesus is THE WORD and those who do NOT have HIS WORD as their FINAL authority have No TRUTH and NO ETERNAL LIFE. The price of listening to 'another' is for eternity - the deceiver who takes his LIE and wraps it in a bit of truth is 'food' for the children of the dark. They ate it on their own accord as they REMAINED unteachable to the things of God but bowed to 'man and it's deceptive teachings.
This one sentence sums up every single difference between Catholics and non-Catholics.