The poem starts with two facts from science. Color comes from how light behaves, and wetness comes from how many water molecules interact, even though no single molecule is "wet." In both cases, something we feel is solid and real turns out to be an effect of a larger performance, not a property of any one part.
Then the speaker turns and asks you directly what that means. The answer is blunt. If it means nothing to you, you're lucky, because you can get on with life untroubled. If you can't help hunting for patterns and symbols, you're in trouble. The swearing at the end drops the calm, lecture-like tone and lets the frustration show.
The mood is wry and a little bleak. The speaker seems to see meaning as something we build from nothing underneath, and the title, "The Damned," suggests that people who keep searching for it are the ones who suffer.