Please correct me if I'm wrong: within living memory, a large area of land already occupied by many humans was unilaterally declared not to belong to them anymore, and they were largely either forced out or subjugated to make way for a different batch of humans who wanted to live, literally, in their houses.
My nation did something very similar to the Native Americans more than a century ago, and it's now universally regarded as an atrocity.
Of course none of this means that suicide bombers are justified or that Israeli children are war criminals. The world is more complicated than that, as you say; whole generations of innocent Israelis have now grown up on that land, and no more deserve to be forcibly displaced than the original occupants did. But I've never heard a convincing justification as to why the occupation was morally justified in the first place, and it doesn't become more justified with time.
My nation did something very similar to the Native Americans more than a century ago, and it's now universally regarded as an atrocity.
Of course none of this means that suicide bombers are justified or that Israeli children are war criminals. The world is more complicated than that, as you say; whole generations of innocent Israelis have now grown up on that land, and no more deserve to be forcibly displaced than the original occupants did. But I've never heard a convincing justification as to why the occupation was morally justified in the first place, and it doesn't become more justified with time.