Because Yiddle took the fall AND MADE SOMETHING GOOD COME FROM IT HIMSELF!
Hashem placed his parents there, in the middle of the fall, to create this positive possibility. Yiddle had a choice, he could have kept walking. HE MADE IT GOOD by choosing a better path, a path that was NOT selfish, and it became healing for all of them.
Sometimes, to jump higher, we need to crouch down first.
Good Day, Dark. Nice to see you. BTW, check out Sefer Tomar Devorah. I forget off hand in which of the 13 middos he mentions this, but he talks about what it means that the Tzaddikim can not stand in the same place as the Baal Tshuvah. That's because the Baal Tshuvah ends up on a higher plane. And One can't become a Baal Tshuvah without the aveira first. perfect example of how something good can come out of something bad.
Kol Tuv,
Steve.