The schoolhouse was an intentional target - the children of some military leaders went there. They triple-tapped the school hoping to kill parents going in to save the kids.
That doesn’t make much sense based on Irans own statements. Three Tomahawks yes. The strikes were reported as being in quick succession. 4 parents were reported as killed and 100+ kids and nearly 30 teachers. Basically it killed the teachers and little kids. No attempt at the responding parents like you incorrectly imply.
How is that better? If true then that would be an even clearer war crime.