A reluctance to follow traditional, pre-world wars law of war.
This point harks back to point #1 and is both a result of and reaction to the high cost of the two 20th century world wars. In the contemporary world the traditional laws of war, that is the agreed upon rules that predate Geneva are considered too harsh. It has apparently never occurred to an academic that the laws of war are harsh for a reason, as though war is supposed to be some collegial contest like a sporting event. They substituted ideals for a realistic appraisal of effectiveness.
Let’s use an example. Traditionally, when a city or other fortified place is under siege if the siege reaches a point where it is essentially a foregone conclusion that absent outside help the place will fall and the besiegers demand surrender but the place refuses, then the besieger was fully within his rights to sack the city or fort and do what he will with the defenders and inhabitants. This is where the notion of raping and pillaging comes in because that is exactly what happened. Think of the sack of Jerusalem in 1099 by the Crusaders. The crusaders invested the city and demanded the surrender of the inhabitants who of course refused. The crusaders then took the town by storm. What followed was by any account a massacre. Essentially the crusaders killed every adult male in the city regardless of faith but killed every Muslim and Jewish inhabitant of the city and taking the women and children and selling them into slavery. Perhaps crusader Jerusalem was not a good example because it is likely the crusaders would have sacked the town even if they did not have to take it by storm.
Prior to the world wars there was a semi-codified set of laws of war, known as the Jus Armorum, which acted more as a brake on bad behavior by combatants than any punitive code. To be fair, these laws were really only held to be operative when two Western nations were fighting each other. They went out the window in colonial wars and wars between Western and non-Western peoples. That does not mean this code was useless or not applicable to contemporary war. It just means that perhaps this older cod4 should be taken to apply universally. This would make waging war both more effective and would shed the universal human rights/civilians are inviolate garbage that has invaded Western thought on war in the post Word War era.
These laws of war covered such things as legitimate targets, treatment of prisoners, prohibited acts, legitimate weapons, faking surrender, etc. It was very similar to modern Law of War except to the method of enforcement. Traditional law of war, unlike its modern equivalent recognized that there was no real legal method of enforcing the laws of war except for exceptional violence. For example, if an enemy faked surrender to ambush attacking troops that was a violation of the laws of war and the only way to punish the offenders was by failing to grant quarter to the unit that feigned surrender. It recognized that ultimately, death is the only meaningful punishment for violations of the laws of war and that group punishment up to and including civilians was a legitimate tool to compel an enemy to fight according to established norms. This infliction of death on the guilty parties as the only practical means of enforcing the laws of war is what is traditionally known as a reprisal.
Let us talk reprisals next. When reprisals are mentioned it is not the kind of reprisals that the Nazis were famous for during World War II or that other countries have engaged in prior wars where villages are razed if partisan attacks or Francs-Tireurs, as they were known prior to 1939. A reprisal in the traditional sense as mentioned above is the only practical way to enforce violations of the laws of war.
Logically then, the proper response of the West to terrorist outrages would be to summarily execute terrorists when they are caught and to refuse them quarter on the battlefield. Using the Clausewitzean principle that warfare tends to extremes the corollary is that if the refusal of quarter does not cause terrorists to limit their outrages then reprisals should be extended to the families of terrorist and ultimately to all members of societies that support and/or harbor terrorists. It should be further mentioned that the battlefield is not the place to separate the guilty from the innocent. Terrorists and terrorist supporters only option should be capitulation with the full expectation that if found to have committed terrorist acts they are subject to summary justice, not the tender mercies of Western constitutional law or legal tradition. Terrorism is an act of war, not a crime and treating it as criminal activity only emboldens the terrorists who use our own traditions of fairness and justice against us. Why should we let them do that? If terrorists put themselves beyond the pale by their actions, then they should remain there.