They are also making Peter out to be a great liar.
Peter, in Acts in the vision with the clean and unclean animals, states that he had never eaten anything unclean.
There are several issues there.
First, if Peter had understood that Jesus meant to eat his real blood, then as an observant Jew by his own admission, he would not have partaken of the bread and cup at the Last Supper.
It was also critical for the disciples that they remain ceremonially clean to be able to observe the Passover.
The other problems are that which you pointed out and is twofold.
Not only would Jesus not have been sinless if He had eaten the flesh and blood, He would also have been guilty of sin for causing others to sin. He COULD NOT have demanded that others knowingly break the Law.
Not to mention that HE then called the wine (the cup) the *fruit of the vine* which clarifies for all that it was simply wine.
So it’s clear that Peter understood that Jesus was speaking metaphorically when He served the elements and spoke His piece.
And the rest of the apostles. I find it interesting that all of the apostles would agree that all should be admonished not to eat blood all the while knowing (according to Catholics) that they expected people to eat blood.
So, then, what does it mean when in 1Cor.11:27, it says therefore if anyone eats this bread and drinks of the cup of the Lord unworthily, he will be held to account for the Lord's Body and blood and :29 where it says he is eating and drinking damnation to himself if he eats and drinks unworthily not recognizing the Lord's Body for what it is