The Platta don't have a concept of gods, so in that sense they are atheist. They do however think the symbolic meaning of all things can be found in colors. To them, it is another sense, and not even figuratively. Their brains are built in a way where it works like one. The way the symbolism applies has some variance like music taste. We might like different music forms and think some are too loud or too boring, but we recognize it as the same song. The Platta don't know others lack this sense, though.