often asked of me as soon as I mention that I study martial arts
The color of the belt I wear around my waist while I am training in karate means absolutely nothing in the real world to anyone besides my sensei and I. A "black belt" is not a quantifiable entity. There are people who have been awarded black belts who can't fight their way out of a paper bag. Likewise, there are streetfighters who have never studied martial arts who are better fighters than "blackbelts".
Within different styles of martial arts and indeed even within different individuals who study the same style, blackbelt level represents such a varied set of abilities that to compare black belts with each other, let alone someone who has not reached that level is pointless.