The problem is that almost everyone I see, including well educated and respected individuals, tend to look at things in a moral vacuum.
From that perspective, what they argue is logical, but in the larger picture it is really flawed.
Say, in 1948 after Israel established its state. The Arab league attacked them with the goal of erasing them from the map. But being so sure they would succeed, they evacuated civilians from the surroundings. After they failed to erase Israel, and in fact Israel took control of the surroundings, should Israel just welcome back the people that tried to erase them, and wait for round two, three, or however many rounds already. In a zero sum game like security and war, the answer is obvious.
Lets look at 2005, when Israel unilaterally dismantled 21 settlments from the Gaza strip, and de facto ended the occupation of the Gaza strip withdrawing its troops from the region. This in theory could have been a golden chance for a two state solution, as Gaza and the Palestinian authorities became sovereign. But guess what? 2006 Elections in Gaza come around (after ten years) and guess who gets voted into power? That's right, Hamas. At that point, from the reading I have done, any sort of diplomatic solution was over.
Now about the moral vacuum, a perspective that I myself have had to change.
Premise: In International Humanitarian Law a combat action must be neccesary to achieve a legitimate military aim, and the benefit be proportional to the risk to civilians.
Assume there is a building with a improvised rocket factory (water pipes and what not), where 2 civilians live. If the expected risk of those rockets is the death of 100 civilians. Is it legitimate for nation A to kill 2 civilians of nation B to safeguard its own. Based on INT Humanitarian Law, even two for two would be proportional.
Now its very messy stuff, various philosophies one can rely on, but in the real world there is no moral vacum. Decision makers do not look at the bombing of the rocket factory and say, killing these two civilians is wrong in principle. Rather they use the calculus above, looking at the larger picture. And we have seen this time and time again.
When the US bombed Hiroshima, then Nagasaki. If looked at from a moral vacuum its a terrible tragedy. And it is. But Truman and the state wanted to avoid a land invasion which would have killed far more than a couple of hundred thousand people (
https://en.wikipedia.org/wiki/Pacific_War ; >26mln death just on allies side 37-45) . We only remember Hiroshima and Nagasaki because the atomic bomb was used. But if one looks at the other strategic bombing operations over Japan, up to 600,000 people died from conventional strategic bombings, while around 300,000 from both atomic bombs combined. Now extrapolate a long land invasion, and perpetual conventional strategic bombings of mostly wooden cities, and the calculus I mentioned earlier becomes evident. (
https://en.wikipedia.org/wiki/Strategic_bombing_during_World_War_II)
I do wish we lived in an ideal world. But the world is a mess.
Edit: The rocket example is not hypothetical, from open source intelligence I have seen quite a few such on twitter. eg:
