

🤷♂️ because when we flip all their quantum numbers we still call them a photon? They have no charge, so if you flip their charge they still have no charge. They have no color, so if you flip their color they are still colorless, etc. The ability of a particle to interfere with itself is a general property of all particles, because all particles are probability waves, so this isn’t special to a photon.
I did use a lot of words to say “I don’t know” didn’t I.