Ridpath's poem is about hitting a barrier again and again and not understanding why it's there. The speaker begins by calling the brick wall a protector, but quickly turns on it: it is mighty and tall, yet it has never softened a single fall. That gap between what the wall is supposed to do and what it actually does drives the first half, and the childlike repetition of "Why are you so tall" and "I wonder that's all" makes the frustration feel simple and worn out.
Then the tone shifts. The speaker claims to know why we exist and why we hurt, but admits to knowing "only this." The poem suggests that answers are frightening, so the speaker would rather get lost in questions. The final lines turn inward: maybe the wall is something the speaker built, and the closing plea to empty the head of fears sounds tired and exposed. The mood is raw, restless, and quietly vulnerable.