The Biblical state of Israel only existed for about 300 years.
In around 1000 BC, King David conquered Jerusalem and carved the state of Israel out of a chunk of what had been, for the previous 1000 years or so, the land of Canaan.
The Israelites felt compelled to conquer Canaan because their God told them they could have Canaan. That and the force of arms was their only claim to the land.
Israel thrived, more or less, until about 722 BC when it was conquered by the Assyrians.
Then conquered again by the Babylonians in 586 BC.
Then conquered again by the Persians about 50 years later. The Persian remained in control of the area until Alexander the Great conquered it around 331 BC.
After the death of Alexander, the area bounced around in limbo until it came under Roman rule in about 164 BC. This is when the area became known as Palestine.
At no time during the previous 2000 years was the area populated by a Jewish majority. It was populated by a mix of indigenous people who had been inhabiting the area continuously for 10,000 years. The Jewish people were just part of the mix.
The Roman Empire ruled Palestine until about 300 AD. The Byzantine Empire ruled Palestine from about 300 AD until 638 AD when the Muslims took control and held it until it became part of the Ottoman Empire in 1517.
The Ottoman Empire remained in control of Palestine until the end of WWI when it was divided between the British and the French.
Although there was talk of establishing a Jewish homeland in the area, it wasn't until after WWII that the British finally punted, turned the issue over to the newly formed United Nations and let them decide what to do with Palestine.
The U.N. basically split Palestine into an Arab Palestine and a Jewish Israel in 1947. That was just 64 years ago. It was not a popular decision then and it has not aged well.
Imagine if the United Nations decided to split Texas in half and give half of it to the Mexicans. The displaced Texans and the neighbors in the surrounding states might take issue with the decision.
Imagine further that the Mexicans decided that half of Texas wasn't enough and went to war with Oklahoma, Arkansas and Louisiana to annex even more territory. Ya know, for "security".
So, let's just take a step back here.
Over the course of the last 10,000 years, Israel existed for 300 years because their God said so and again for the last 64 years because the United Nations said so.
When you look at the big picture, telling Israel that they can't keep the land they took by force in 1967 and need to pull back to the land that was taken from the Palestinians and given to them in 1947 doesn't seem to be all that egregious.
The bottom line here is that the only reason the state of Israel exists again after
3000 years is because the United Nations took a chunk of land away from one group of people and gave it to another group of people. It's not as though it was brought into existence by God Himself and has remained inviolate for all of human history.
Israel is a consensual construct of modern international law. It's borders were negotiated into existence against the will of it's neighbors and they can only be maintained through continuing negotiations with those same, hostile neighbors.
If world history teaches us anything, it's that nothing lasts forever.