More true than many willing to admit. Most of the 'decodes' or proffered explanations of ancient symbols by well-known and well-loved people are wrong, many really far off the mark. That is not to say there is no evil or no evil cult or long-running evil, there is. But very ancient beautiful symbols were coopted and used in ways to defile them in order to conquer the good they represent.
You are quite right about narratives being made up in the last couple hundred years, and it is to fit an agenda, somewhat inside of the evil agenda, sometimes unbeknownst to those who are putting them forth or others who learned from them and just repeat those explanations. It is very easy to get people to willingly swallow the false narrative if it is couched comfortably in the terminology and are made to fit inside the stories of a religion.