What does the quot a critic is a legless man who teaches running means?

The quote "a critic is a legless man who teaches running" suggests that critics often lack personal experience or capability in the areas they critique, yet they still offer guidance or judgment. This metaphor highlights the irony of someone providing advice or evaluation without having the necessary ability or firsthand knowledge to truly understand the subject. It implies that critics may not fully grasp the challenges faced by those they critique, making their insights potentially superficial or misguided.