Well, you got the purpose of the "Where's Daddy" program wrong, apparently on purpose. They weren't watching a terrorist and just kicking back until he got home after a long day at the terrorism office so as to "purposely kill civilians". They identified terrorists and then watched their families for any contact.
This is intelligence 101, anyone who doesn't want to be found needs to cut all contact with their family--but people are flawed and they often make the mistake of establishing contact.
It's been a heavily-used tactic in counter-intelligence at least since ww2 but you could probably find examples from hundreds of years ago if you went looking, it's a pretty obvious flaw. Just going with the Zarqawi theme though, it is how the Mukhbarat foiled his 2004 Amman chemical attack plot--the bomb-maker sent operatives to pick up his family.
And, yes, sometimes this results in the death of family members or other civilians. I think like 4-5 civilians died in the thousand pound bombing of Zarqawi I already mentioned. That's no good, but war is hell and sometimes you have to make impossible choices. Let a guy go who may kill 80,000 people or kill him along with 4-5 civilians who support him? I'm very grateful that I don't have to make those choices so I can't judge the people who do.
This is the constant flaw in giving Israel the benefit of the doubt. I hear "war is hell", "unintended consequences". as if this war is in such heavy fog that the consequences are unknown. Israel has and continues to shoot at suspected terrorists that are imbedded in civilians and then say "well we have no choice". of course they have a choice, they can not fire into the civilian areas. they mark spots on a map and say these are the safe zones, here are your corridors to get to those safe zones, and when you're there it's a refugee camp. then they bomb the corridors, and bomb the camp. and say "guys we had zero other options, there was hamas fighters there".
i do appreciate your examples, but the numbers you listed at the end are absurd in this context. Hamas carried out it's most deadly attack it's ever had by a dozen orders of magnitude. previously they had attacks that got like 3 people killed. on 10-7 they killed about 1195 people, 367 service members, and 828 civilians. Since then Israel has killed at least 72k people, with 172k wounded and almost zero medical care.
at the end of the day, the math would say "kill 250k people to save 1.2k people". and that's assuming israel would have done nothing in the wake of 10-7 to prevent another attack. when any smart country would seriously bolster their defenses after barbarous impoverished terrorists walk through your border like it's swiss cheese. and they'll bolster the defenses and lock down that border after the war anyways. we'll see new walls, new guard posts, increased sensors, etc.
its easy to justify a war when you see the cause for the war as not only just but required. all anyone has to do is ask if the war was needed at all and the whole thing falls apart. 250k people at least dead, israels world wide reputation destroyed, all to build a wall they could have made without the war anyways.