Well, according to the Western media/political class –
a human shield is a civilian in Gaza who is killed in an Israeli air-strike aimed at Hamas (and carried out by a donated US war-plane).
But a civilian who is killed by a strike carried out by the Syrian air-force in Syria aimed at armed groups trying to topple the government is ‘a victim of a murderous regime’.
The moral narrative put out by the West is entirely selective. They turn it on and off to suit whatever madcap regime-change adventure they are currently launching.
For example; after Saddam Hussein gassed Kurdish villagers the British government (the Thatcher government) didn’t bat an eyelid. In fact shortly afterwards they dispatched a government minister (Tony Newton)  to Baghdad to talk up a trade deal. But after he invaded their little oil haven (Kuwait) he was put on a watch list.
As always in these cases the pivot – from darling dictator (or at least ‘someone we can do business with’) to absolute monster with whom it is impossible to negotiate and who must be eliminated is accompanied by a suitable narrative in the press. For example; at the time of the Iraq invasion in 2003 the gassing of Kurdish villagers in 1988 suddenly started being used as an example of how much of a monster Saddam Hussein was. More recently we have the narrative that Assad is ‘murdering his own people’ and before that the narrative that Gaddafi is ‘about to murder his own people’. The political class/media class talk up the moral narrative which ‘justifies’ the invasion. Yet they were silent before. Again; notice how the political and media classes became so concerned about the rights of women in Afghanistan – but only in as much as this was deployed as another moral argument to legitimize an invasion. Prior to the decision on invasion there had been no publicly expressed concern about the rights of women in Afghanistan. As there is none today about the position of women in Saudi Arabia.
This selective use of morality in the service of resurgent imperialist aggression is a hall-mark of the current regime in the West. The press manages the narrative about morality on behalf of the regime.
1 John Pilger. The New Rulers of the West. Verso 2003. In Chapter ‘Paying the Price’ (p66 in 2003 edition).