See what you insight is doing? Like I said, BRILLIANT insight brother.
RCs tell us that we are to understand the eating the flesh and drinking the blood literally. Think about the position the RCs here are arguing. The unbelievers who left Jesus ... they were the ones who took the sayings of Jesus literally. The ones who responded "How can this man give us his flesh to eat ... " ... are the ones who walked away.
So the RCs here are in the embarrassing position of supporting the view of the unbelieving masses (no pun intended) who left.