Dreaming is an art, and skill is inherent in any art, whether dreaming, massage or juggling.

Maybe the author's intent in the statement is that we think of lucid dreams too rigorously and with a great deal of focus on the scientific side, AKA the manifold techniques and substances that can induce such a state. Maybe, this laser-like focus is to the detriment of the true art, which is cultivating the inner spark of lucidity, the access to the flow state that can come upon us at any time, day or night, waking or sleeping.

The way I see it, the fascinating science behind lucid dreaming are the training wheels that tell the world, "This is possible." For dreamers, the art is in enjoying the ride.