It’s not even close to that simple.
“They” is not fungible. Each person is an individual. The children killed, if they were, didn’t attack anyone and aren’t able to attack anyone. They’re children. Duh.
Hamas terrorists attacked tons of people, and continue to shoot at Israeli troops coming to get those terrorists, and killing them at times. The civilians in Gaza are being deliberately used as human shields by those terrorists, but it’s not like they have a choice in the matter, once some terrorists are among them.
The majority of Gaza civilians are under 20, which means they never even got a chance to vote for their government, since the last election was over 20 years ago.
The whole thing is one huge sh!t show, which has been going on for 103 years, ever since the Jerusalem pogrom of 1921 or 22. It’s unlikely to get better, and for any hope of making it better, Hamas MUST be eliminated, only they do hide behind civilians and civilian areas. And they do have a powerful propaganda machine, which circulates far and wide the narrative that Israel is attacking civilians. So part of eliminating Hamas is defeating their lies on the merits, and circulating the refutation far and wide, and it would certainly be helpful along those lines if they can be proven to be lies.
And when the Muslims howled about Israel getting their own nation too, the Allies delayed until WW2. Thus a compromise was made: a two-state solution. Those two states were Jordan and Israel. The Jews living in the new nation of Jordan had to move to Israel, and Arabs living in the new nation of Israel had to move to Jordan. Only, the new people moved to Jordan put up a fuss and tried to take over. Thus making them unlivable in both Jordan and Israel.
Later, Egypt and other Muslim nations tried again to take over Israel...from Gaza. Thus, Israel took over that land. Egypt doesn't want those people back because they're nothing but troublemakers for Egypt, just like they are for Israel.
And the precious youth you talked about, have all been taught from birth to destroy Israel "from the river to the sea". Have they learned their lesson to not do so? Evidently, the "children" haven't been spanked enough.