Not taking sides on the attack, but, wow, you ommited half the text - important in this context:
"unless either:
(a) they are placed on or in the close vicinity of a military objective; or
(b) measures are taken to protect civilians from their effects, for example, the posting of warning sentries, the issuing of warnings or the provision of fences."
"unless either:
(a) they are placed on or in the close vicinity of a military objective; or
(b) measures are taken to protect civilians from their effects, for example, the posting of warning sentries, the issuing of warnings or the provision of fences."