people's egos. there was a 'yellow tort' a while back that the people with it were desperate to think it was a super rare fancy coral. all other torts were blue, so being yellow made this OMG_RARE!!!1 in their minds. the closest thing to experts we have in the hobby later confirmed that is was not a tort, but rather an austera. but pride kept them calling it a tort regardless, and with that one called a tort, other people, either trying to cash-in and increase marketability, or through simple ignorance started calling other austeras as torts.
not that the word tort really had any real meaning to begin with, other than 'blue knobby stick'.