Why are these 'worthless men' so fundamentally unusable, even when people might try to harness them?
The key phrase is 'they cannot be taken with the hand.' This isn't just about physical inability; it's about their inherent nature. Thorns are designed to prick and repel, not to be held or used for good. Similarly, those described as 'worthless' here have a character that resists being guided, utilized, or shaped for positive purposes. Their actions and intentions are ultimately destructive, making them unfit for any noble cause or beneficial relationship. They are set apart for rejection, not for service.