It is not a real contradiction. Insulators are indeed imperfect. One can almost as easily highlight the extent to which these waveguides are Topological Conductors. Call them Topological Semiconductors, if you will. "Robust against imperfections" is not perfect either.

What is cool is extreme-scale geophysics meaningfully interpreted as Quantum Analogs. ENSO and QBO can be modeled as Phonon Physics, using Feynman Diagrams. Planetary Tidal Phonons (wave packets) are at the cutting edge of current geoscience. In a sense, a Tidal Bulge traveling around the world is the same ancient Phonon that daily tunnels across the North and South American barrier. There was objection over such avant-garde interpretation of hurricanes crossing Central America, earlier...