You have asked a nice question. Many are having this doubt, that is whether Judas is to be venerated or not. From my experience, some Muslims and Bible critics also ask these question.
Jesus' crucifiction and death is ofcourse planned from the beginning.
Prophets were proclaiming it. Judas did a wrong thing to betray his Teacher.
We have no doubt. But, the doubt is that, because of this betrayal only, we could attain salvation. So why should not Judas be praised? It is just because of the fact that he had done the sin to betray his teacher. But the God can tranform a bad doing to a good. Just like, Moses did a sin to kill an Egyptian, but he fled afraid of Pharaoh and then God used the oportunity to select him as a prophet. There are hell a lot of examples from the Bible itself. When we closely observe our lives, this is still happening!! One must have done a wrong thing to you, but God make this an opportunity to bring a good prosperity out of that.
So the sin of Judas was tranformed to a good by the Lord. And that is the truth. So a sinner and sin cannot be venerated. And there is a term called 'free will'. If we want to do sin, God will never interfere in that. That is we have the prevelage to select good or bad in our lives. This is what is meant in Lord's words to Caen "The sin is at the door.....". Adam and Eve was given the prevelage to eat the fruit or not. We are still having that prevelage. But God will warn us through many mediums. Judas was also warned many times. We can see Jesus warning Judas even just before the Last Supper. Still he was not turning his heart, so Jesus was just leaving him like "Do
what you have decieded". That is not a permission.
About the second doubt, that is Satan entered Judas' heart when he recieved the Holy Eucharist. That is a clear explanation of what will happen when Eucharist is consumed by one who is unholy or with his sins. Judas was with his heart unholy, consumed the Euchartist and Satan entered. But the other Apostles also consumed it, but recieves the blessing and Holy Spirit.
Dn. Bennet Kuriakose