I would love to know which Iranian proxy Israel "directly created". You might be confusing Hamas with Ahmed Yassin's previous charity, which ran schools, mosques and clubs. Even that charity was not "directly created" by Israel, Israel merely allowed them to operate.
Well yeah, but they still had a chance to play the victim after the US/Israel strikes (especially if some of the reports about how the negotiations went down are true). Lots of people are still primed to listen to it. But they're not interested in making it easy for their apologists, I guess.
Assuming that happened, I guarantee it was a targeting error. The US and Israel have no actual reason to target children, seeing how they have plenty of useful military targets and want (or at least need) the Iranian people's support for regime change.
For what it's worth, Iran has claimed their strikes on Oman were mistake, and I believe that too, since Oman seems to have genuinely been trying to help them. Just Oman though. They apparently feel fine about all the other strikes on bystander nations.