The doctrine of the Elect of God is also sometimes referred to as , the Doctrine of the Elect of God, or, The Doctrine of Predestination.
It does appear to be contradictory when you put your inquiry into those words. When Jesus died for all why is there that group called the Elect of God?
This topic has been discussed elsewhere on this site so I'll share with you a link to a questions site that focuses on your query.
Question: "Who are the elect of God?"
Two excerpts from that article if you don't feel like reading a single page article.
As it stands, the concept of God electing those who will be saved isn’t controversial. What is controversial is how and in what manner God chooses those who will be saved. Throughout church history, there have been two main views on the doctrine of election (or predestination). One view, which we will call the prescient or foreknowledge view, teaches that God, through His omniscience, knows those who will in the course of time choose of their own free will to place their faith and trust in Jesus Christ for their salvation. On the basis of this divine foreknowledge, God elects these individuals “before the foundation of the world” (Ephesians 1:4). This view is held by the majority of American evangelicals.
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The second main view is the Augustinian view, which essentially teaches that God not only divinely elects those who will have faith in Jesus Christ, but also divinely elects to grant to these individuals the faith to believe in Christ. In other words, God’s election unto salvation is not based on a foreknowledge of an individual’s faith, but is based on the free, sovereign grace of Almighty God. God elects people to salvation, and in time these people will come to faith in Christ because God has elected them.
The difference boils down to this: who has the ultimate choice in salvation—God or man? In the first view (the prescient view), man has control; his free will is sovereign and becomes the determining factor in God’s election. God can provide the way of salvation through Jesus Christ, but man must choose Christ for himself in order to make salvation real. Ultimately, this view diminishes the biblical understanding of God's sovereignty. This view puts the Creator's provision of salvation at the mercy of the creature; if God wants people in heaven, He has to hope that man will freely choose His way of salvation. In reality, the prescient view of election is no view of election at all, because God is not really choosing—He is only confirming. It is man who is the ultimate chooser.