Etiquette rules usually treat women as delicate, in need of protection. Here, the speaker flips that idea. Each "rule" for gentlemen comes with a reason that has nothing to do with politeness: a lady's skin burns hot enough to ignite wine, her gaze is dangerous to bystanders, and her passing creates a whirlwind. The gentleman isn't protecting her. He's staying out of her way, or shielding everyone else from her.
The tone is deadpan and playful. The speaker keeps the formal voice of a manners guide while the examples grow more outlandish, ending with a lady who stuns a driver, seizes the reins, and gallops toward invading hordes. The humor comes from that gap. Underneath it, the poem seems to admire these women openly. They hold up civilization itself, tapping loose bricks back into place with a white-gloved finger. The mood is witty, affectionate, and quietly subversive, as if the old customs were always a polite way of making room for someone formidable.