From the International Committee of the Red Cross Casebook. TLDR, the idea that civilians voluntarily standing around a civilian object counts as the crime of human shielding is legally incoherent and would effectively nullify the protection for civilians. Something we have seen repeatedly in Gaza as Israel effectively claims that all infrastructure is a legitimate military objective and therefore all civilians are being used as human shields no matter where they are, which has effectively eliminated even the possibility of distinction.

Some consider that acting as voluntary human shields constitutes direct participation in hostilities, which would cause the persons concerned to lose protection against the effects of hostilities while they act as human shields. Others object, first, that in order to classify an act as direct participation, the act must provoke, through a physical chain of causality, harm to the enemy or its military operations. Human shields are a moral and legal rather than physical means to an end: to hinder the enemy from attacking. Second, the theory considering voluntary human shields as civilians directly participating in hostilities is self-defeating. If it were correct, the presence of human shields would not have any legal impact on the ability of the enemy to attack the shielded objective – but an act which cannot have any impact whatsoever upon the enemy cannot possibly be classified as direct participation in hostilities. Third, the distinction between voluntary and involuntary human shields refers to a factor, i.e. the voluntary involvement of the target, which is very important in criminal law and, to a lesser extent, in law enforcement operations, but is completely irrelevant in IHL. A soldier of a country with universal compulsory military service is just as much (and for just as long) a legitimate target as a soldier who is a member of an all-volunteer army. Fourth, the distinction is not practicable. How can a pilot or soldier launching a missile know whether the civilians he observes around a military objective are there voluntarily or involuntarily? What counts as a voluntary presence? Fifth, in a self-applied system like that of IHL during armed conflict, the suggested loss of protection against attacks may prompt an attacker to invoke the prohibition to use human shields abusively, as an alibi, as a mitigating circumstance or “to ease his conscience”.

https://casebook.icrc.org/law/conduct-hostilities#ii_8