"How often would I have gathered together thy children. This is expressive of indignation rather than of compassion"
How could God express "indignation" for something He planned and ordained? Seems He would be expressing satisfaction that, for once, people did what they were preordained to do.
A better question is how could God be surprised by the actions of His creatures?
It is a teaching verse. One among many.
People always do what they were preordained to do.