Multiple sources including scientific journals, have backed up the death numbers. [1][2] I get it probably makes it easier to sleep to think Israel isn't murdering thousands and thousands of kids but that's the truth.
Are you okay with killing a Palestinian child if it would kill a Hamas member? Would you personally be okay pulling the trigger? Palestine has one of the youngest populations in the world and is one of the most densely populated areas. Dropping endless bombs is going to kill kids. Israel says it's to kill Hamas, so they're happy to kill children to make that happen. Are you?
If you would kill one child to kill a Hamas member, would you kill two? How many dead kids would it take for you to personally say, "maybe that's enough dead kids, regardless of any supposed benefit, I can't kill any more kids"?
[1]https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(23)02640-5/fulltext
[2]https://time.com/6909636/gaza-death-toll/
"Your authoritarian rulers kidnapped some of our people so now we get to kill innocent people with impunity" is a super shitty take