"To perpetuate the myth" means to continue spreading or promoting a false or misleading idea or belief, making it widely believed or accepted by others. Full definition
She is saddled with the unenviable task of perpetuating the myth of Mad Tracey from Margate, which is the source of all her power, while also drifting gently into middle age and maturing as an artist to ensure her longevity. (fadmagazine.com)
It's the rare masterpiece that manages to have its cake and eat it too, critiquing the role of movies in perpetuating myths about violence while also bringing both its subject and the audience to greater insights about their own propensity for it. (moviemezzanine.com)
So they persist in perpetuating this myth in order to sell product. (drperlmutter.com)