What appears as clarity vs. delusion obviously depends on where we are at ourselves. It is, as so many things, relative to our viewpoint.
There are horizontal views of delusion, where Christians see Muslims and deluded and vice versa, where those enjoying classical music see heavy rockers as deluded and vice versa, etc.
And there are vertical views of delusion. Having awakened as a small self, we see "lower" animals and plants as not quite as highly evolved. When we awaken to Drop Big Mind, we see those who are identified with the small self as deluded. And awakening as Ocean Big Mind, we see the awakening as Drop Big Mind as not quite there yet.
This means that if we use the word delusion to describe someone else, we simultaneously describe ourselves - as seen from another, horizontal or vertical, viewpoint.
And there is a symmetry and great beauty in this.