This was interesting found at least, but I am sorry to say it is based on a thin proof.
The fact is, according to the article by Walter E. A. van Beek which was published in Current Anthropology in 1991 (Volume 32, Number 2, April), that
he couldn't confirm the Griaule's ethnography, but furthermore, he can't even regonize the tribe itself from Griaule's description.
Before Griaule, there has been other ethnographists and anthropologists whose description doesen't match Griaule's one. But nevertheless, van Beek
went there to commit a restudy and found out that
Dogon - just like other Mali tribes - had no idea that Sirius was doublestar..
The Dogon know no proper creation myth; neither the version of Ogotemmêli or that of the Renard pâle is recognizable to
informants. The figure of Ogo (RP) is unknown; the fox as a divining animal has no privileged position in mythology. That Sirius is a double star is
unknown; astronomy is of very little importance in religion.
Source: CA Vol. 32 No. 2 April
van Beek also recognized, that creational myths in religions can be restricted from public knowledge, but suggested that there should be at least
traces of it visible:
The problem of secrecy in culture is a complex one that has as yet received little theoretical attention (cf. Bellman 1984). Of course, cultures
do contain elements that are readily disclosed to outsiders [...] hidden not only from outsiders but also from the majority of the population.
Source: CA Vol. 32 No. 2 April
The question is, in my opinion at least, why does Griaule's description of Dogon religious myths contradict with the reports before and after his
study? In my opinion, they have perhaps tried to start a new
New Age-myth. Another possibility is that they learned about all this stuff from
European conquerers, but that's far fetched, as it wasn't common knowledge in Europe either. 3rd option is that someone is trying to hide something.
Maybe they have these rituals after all, but no one wants to admit it

Go see it yourselves.
Sincerely