Because Blackmagic is no product partner.
They are "contributor".
I think the Academy is inspecting your ACES implementation if you want to be a product partner and see if your implementation is really good. And I personally would say that the implementation in Resolve is (at this moment in time of version 12.5) not really good But that may change.
Still I am using ACES in Resolve. But it's a bit harder than it should or could be. And things like "Davinci ACES" are probably a no-no.