Wilde cuts through sanctimony by suggesting that morality isn't about discovering some perfect universal standard—it's an act of creation, closer to artistic choice than mathematical truth. Notice he doesn't say morality *is* drawing a line, but *means* drawing one; the verb captures the deliberate, even artificial quality of where we decide to place our boundaries. A parent deciding whether to let a teenager attend a party late at night faces exactly this: not a self-evident rule, but a judgment call that reflects their values and fears, much like a painter deciding what to crop from a canvas. The discomfort Wilde provokes comes from admitting that our moral lines often say more about us than about objective right and wrong.