I will give you a short answer as to why christians love Israel and will always stand by them regardless of the fact that they not only killed our Lord Jesus Christ but that they have also rejected Him as the Messiah which we know Him to be. It is because the Holy bible specifically requires us to do so and tells us that “He who blesses Israel is blessed and He who curses Israel is cursed”. Christianity came out of Judaism and the new testament of the bible(which is where chrisianity was established and where Jesus revealed Himself) is a fulfilment of the prophecies and promises of the old.
The old testament is essentially Jewish religious history and that is where christianity (the Judeo-Christian faith) came from. Both the christian and the Jew came from Isaac, the promise child of Abraham because Isaac was a Jew and christianity evolved from Judaism. Jesus who was a Jew and was also killed by the Jews specifically enjoined His disciples to carry the good news (the gospel) of His message that He was the son of God to the gentiles because the Jews, from whom He came and to whom He was initially sent had rejected Him. The disciples not only did this but they did it very well. Apostle Paul particularly spread the good news to the gentiles and from there christianity became the largest and most formidable force in the world till today.
In order to understand why christians will always love and support the Jews and the state of Israel despite the fact that they rejected Jesus, you also need to know a little more about our faith. We are taught to love and accept not just those who agree with our faith but also those who hate us and reject us. Jesus died and sacrificed Himself for everyone including the Jews and His word makes it clear that through the ages He has and He always will have a soft spot for them because He was sent to them first even before He came to the gentiles. This deep and unconditional love and understanding is called agape love: it means that we must learn to love even the most unlovable things and people. It means that even when they hurt us, abuse us, reject us and even kill us we must still love them because that is what Jesus did. That special place that the Jews had in Jesus’ heart is the same special place that is in the hearts of every true christian for them. We share a common ancestry in not just Abraham but also Isaac, our Lord came from them and had a special place for them in His heart even though they rejected Him and He specifcally urged us to bless and protect them. They are indeed a special people before God and the christian’s umbilical chord to them is spiritual, emotional, historical, deep, unbreakable and eternal. The killing of 6 million Jews by Hitler made it imperative for the world to return them to the land that God’s Holy bible tells us that he gave to them as their promise land forever. They were returned there(because they were there in the first place) and Jerusalem(which is the city of David) is not just their capital but also the spiritual capital of all christians. So the bond is strong.
Even though christians have persecuted Jews for centuries this should not be so: that is the influence of the devil and he does it because He knows that God loves them so much.
Do you know that the bible tells us that God has assigned Archangel Michael himself to watch over Israel? The bible calls them a “stiff necked people” and it says that though they would suffer for quite some time(which they did more than any other) God would give them back that land that He had promised to their forefathers and that they had originally occupied from the time of Abraham, Isaac, Jacob, David, Joseph and Moses. He promised that it would be a land flowing with milk and honey and that He would subdue all their enemies around them and that they would flourish and excel until the return of Messiah at the battle of Armageddon. That is why the state of Israel can never be defeated. It came by God’s prophecy and it is defended by His promise and His word. Islam came into the world only 600 years after christianity. The muslims derived from the line of Abraham’s son Ishmael but not the line of Isaac, the promise child. The bible tells us that Ishmael’s mother was Hagar and Isaac’s mother was Sarah. It was Sarah son, Isaac, that the Jews, the Christians and the Messiah Himself came from. Therein lies our bond with our Jewish brothers. They may despise our faith and reject our Lord but we will never stop loving them.