All right, let’s look at the timeline for the bigger picture.
Who did God first introduce himself to? (“Hi, I’m God…”)
Abram, right?
So out of alllllll the people in the world, he picked one guy to have a personal relationship with. And enter into a covenant with, including promising his descendants lots of land that was already settled by plenty of other tribes. And then makes another covenant with. And renames him Abraham.
Fast-forward to Abraham’s grandson, Jacob. He also has a relationship with God, and also gets a new name: Israel. And he has twelve sons, who found the twelve tribes of Israel.
Then fast-forward. God has a special relationship with the Israelites, who can all trace their ancestry back to that single founder.
And fast-forward some more. Jesus comes not only to preach to the Jews, but also to redeem humanity and establish a new covenant.
And fast-forward some more. Jesus’ followers are the Christians, who are scattered by persecution-- but in their dispersement, the Gospel is preached throughout the world.
And continue to fast-forward. We’ve gone from God only revealing himself to a single person, to the development of that relationship so that it encompasses his family, the descendants of that family, to the entire world. It’s kind of like an inverted pyramid.
At any point in that inverted pyramid, you can ask, “Why did God choose to reveal himself to Abraham, but not the guy down the street from Abraham?” or “Why did God choose to have a relationship with the twelve tribes of Israel, but not the Egyptians?” or “Why did God choose the Jews as his chosen people, but what about those poor Greeks?” or “The early Christians preached the best they could, but what about those poor Aztecs across the pond?” For that matter, you can ask, “Why did God take thousands of years to reveal himself gradually, instead of inventing a full-fledged worship process right from the start and just dropping instructional pamphlets (“How to Worship Me in 12 Easy Steps!”), Bibles, catechisms, and missalettes in everyone’s laps?”
“Why did God reveal himself via such a gradual process” might be a more honest question than “Those poor Canaanites! Obviously God didn’t love them!”