لأن المراد بها الموت
Because death itself is what is meant by the word.
When al-maniyya refers to death, the first issue is whether it is being used in the respect relevant to its established meaning or whether another claimed respect changes its use. A figurative property predicated of something does not by itself make the noun naming that thing lexically figurative.
The expression has separate elements: “death” and the “claws” attributed to it. One can preserve the literal signification of the first while still analyzing a figure in the second element or in their relation.