I'm curious where that other got this weird dichotomy from, especially since in the case of VtM, the game VtM came first, and the Storyteller System was made from it in order to make more games like VtM; and in the case of CoC, Basic Role Playing came from the game RuneQuest, and then was used to create CoC.
Regardless, whether it's technically a TTRPG or not isn't even that important as long as the game is functional, keep it up and don't let them get to you.