The antonyms for protective walls are "openness," "vulnerability," and "exposure." When something is unprotected or open, it is exposed to potential danger, harm, or attack. Vulnerability implies a state of being easily hurt or harmed, without any means of protection or defense. Exposure means being laid bare or left open to danger, without any restraint or cover. Though the idea of protective walls is often associated with safety and security, being open and vulnerable can also have its benefits, such as fostering trust, communication, and cooperation. So, while protective walls may be necessary in some situations, they can also create barriers that hinder progress and growth.