ESV - 25 Judas, who would betray him, answered, "Is it I, Rabbi?" He said to him, "You have said so.
For follow-up discussion and general commentary on the topic. Comments are sorted chronologically.
Each man must choose what action to pursue. Jesus spoke truth to his disciples and then invited them to partake of the tokens of his body-bread and wine. Jesus did not have to stop Judas from doing anything. Neither does Jesus or any wise disciple have to stop anyone from partaking of the emblems. Give them instead the word: He that partakes unworthily brings damnation on himself. If a man chooses to rebel against the word of God, he is a fool and the pestle mortar treatment of Proverbs 27:22 will not help either. He will quickly listen up one day when he sinks into the manhole of Revelation 21:8, but it will be way too late!
This question presumes that Jesus looked at the "Last Supper" or "Holy Communion" the way many of us do. Jesus did not give us one rule or mandate to follow; the church does that.
Nothing was violated when Judas partook of the bread and wine. The bread was a symbol of Jesus' body that would be broken. The wine was a symbol of his blood that would be shed. The disciples symbolized communing with him in his death by partaking of these sacraments. It's a ritual with meaning attached to it. It doesn't heal, save, refresh, pardon, nothing; it's done as a memorial. It means we are with him in spirit now, and we are waiting and anticipating his return. No covenant was violated by Judas eating at the table with Jesus and the other disciples.
Jesus ate with sinners... (Mt 9:10) That's all he has to eat with... if he eats with people, he eats with sinners.... if he eats with a person, is that person presumed to be saved? No, of course not! Nothing was thought of Judas having breakfast, lunch and dinner with Jesus until Jesus institutes a memorial on his last night as a free man. Now suddenly, he's expected to deny Judas the opportunity to eat with him. Why would God deny anyone his attention? That's not what he does! Some congregations of the church does that. They've never thought up a rule or a mandate that they didn't like.
Instead of celebrating the Passover, which is God's grace toward us, they celebrate a ritual; they think highly of themselves by claiming to be worthy of communion with the Lord while others are not worthy. To be sincerely thankful for being pardoned (passed over) for our sins never occurs to some of us. It's the ritual we focus on; it says we're special; very little real attention is given to the Lord who loves us enough to die for us.
This question says a lot. It says there's the thought that Judas doesn't represent mankind; Jesus allows mankind to dine with him, knowing all along that mankind will betray his love, his kindness, caring, provision, etc.
Judas' betrayal is emblematic; so is his life. I read the question and it reads as if he's one of a kind. When in fact, he represents all who aren't chosen. Their lives come to a tragic end. The soul who sins will die (Ezekiel 18:4).
"Many are called, but few are chosen." Jesus said this to cap off his sermonic parable of the wedding feast in Matt 22.
Judas was one who was called. He, unlike the called of Matt 22, answered the call to be discipled by Jesus. These guests were invited well in advance of the feast being ready. They had plenty of time to consider the offer. When the feast was ready they declined the offer. Then the king sent his servants out to "gather together all they found, both good and evil; and the wedding hall was filled with dinner guests." (vs 10) It doesnt say so, but it's implied that the first group were the so-called elite, the grade A choice crowd. For an unexplained reason they weren't interested in hobnobbing with the king.
The second group were like fish caught in a net; some of all kinds. And then there was one among them that didn't have the proper wedding garments. He was expelled.
This parable followed two others told by Jesus. The parable of a man with two sons, and the parable of the tenants. One son says he will serve his father and doesn't. The other son says he won't serve, but does. The tenants had a sweetheart deal and weren't satisfied. All they had to do was share some of the fruit from the vineyard with the absentee owner. They tried to steal the vineyard instead.
Jesus is describing an ungrateful people. If you think it only pertains to Israel you aren't paying attention. I think Judas had a sweetheart deal; he didn't see it that way...