Husk (or hull): the protective outer covering of some fruits or seeds, which is usually dry and not edible. The term is also used for the outer shell of some insects in the early part of their life cycles.

Withered: dry, shriveled, shrunken, or wrinkled from old age or disease (or both).

Withered husk: old, dry, covering that has outlived its protective purpose and needs to be discarded.

. . . to chew its way free from the useless withered husk of the old:

أن تحرر نفسها من القشور البالية العديمة المنفعة الموروثة من الجيل العتيق

Notice that the word "old" in the sentence is understood to mean "the old generation," as it is clearly meant to stand in comparison with the earlier reference to "the young generation." In Arabic, the noun must be made explicit.

Also notice that the speaker of this sentence does not label the old generation with any pejorative characterization other than being old. Likewise, you shouldn't. Only the husk is characterized as withered.