For one it wasn't targeted, but either way, if it, as you claim, was targeted then it would be even worse because it's worse to kill and maim kids by targeting them than by being indifferent.
Targeting Hezbollah operatives is certainly targeting, yes. The fact that there was still some nonzero harm to civilians, despite the targeting, does not refute that. Targeting doesn't imply zero collateral damage, which is an impossible standard.
How was this not targeted? I was the most targeted military operation we know of. Give me any example of anything in warfare that is close to that.