I think you have a misunderstanding of the concept of 'human shield'. Am going to use as neutral language as much as possible, and if I use
'you', I mean the word in the generic, not personal, sense. Let us see if whoever is behind the forum handle
'khansaheeb' is capable of the same courtesy. But I would not let my hopes up.
In wars, the concept of 'human shield' exists only if one side works somehow to avoid non-combatant casualties. The 'non-combatant' is the proper phrase to denote those who
DO NOT want to engage in combat but since the phrase is commonly associated with 'civilian', I will use the common vernacular. If you chose not to respect that idea, then immediately the concept of 'human shield' comes into play. Whether you actually divert civilians into your battle calculus or not, is not yet the point. So if I am aware that you do not respect the idea of a 'non-combatant', I am immediately at risk in killing civilians in the course of combat. I do not know whether you will chose to use 'human shields' at point A or B or wherever, I just know that from point to point, I have to consider the possibility of civilians
IN THE WAY of combat.
Now, how old is the understanding that soldiers and civilians are not the same and that there are conducts in war? Quite old. Here is one example:
...both Euripides and Thucydides were able to write of the "common customs (koina nomima) of the Hellenes," which,in regard to the law of war, may be summarized as follows:
1. The state of war should be officially declared before commencing hostilities against an appropriate foe; sworn treaties and alliances should be regarded as binding.
2. Hostilities are sometimes inappropriate; sacred truces, especially those declared for the celebration of the Olympic games, should be observed.
3. Hostilities against certain persons and in certain places are inappropriate; the inviolability of sacred places and persons under protection of the gods, especially heralds and suppliants, should be respected.
4. Erecting a battlefield trophy indicates victory; such trophies should be respected.
5. After a battle it is right to return enemy dead when asked; to request the return of one's dead is tantamount to admitting defeat.
6. A battle is properly prefaced by a ritual challenge and acceptance of the challenge.
It should be understood that what conduct was considered 'acceptable' then maybe 'unacceptable' today, but the main point is that across time, cultures, and continents, there is a consistency that some conducts are considered 'honorable' and 'dishonorable' for soldiers.
Note item 3:
Hostilities against certain persons... What could be those 'certain persons'? Every culture sophisticated enough to separate soldiers apart from everyone else, that 'certain persons' class is obvious: non-combatants or civilians.
Israel charged that Hamas divert civilians into their battle calculus. Is that charge valid? If yes, then any civilian death is morally upon Hamas, even if the civilians were killed by Israeli soldiers in the course of battle. If no, then any civilian death is morally upon Israel. Simple as that.
How many ways could you divert civilians into your battle calculus? Many. From literally putting a civilian in front of you, to using a civilian's home to store weapons, to having bivouacs within sight of civilians. In any of these examples, there are
ZERO degrees of moral separation between you and the civilian(s).
Soldiers have the right and the moral obligation to responds to attacks upon them, and if you use 'human shields', the tragedy of their deaths are on you. Simple as that.