???
I thought that they're now only implementing System.DirectoryServices.Protocols instead of System.DirectoryServices.AccountManagement on Linux/MacOS because it's "a) the API was meant to support any LDAP server as opposed to AccountManagement which was more ActiveDirectory only, and b) the API in Protocols would give you most of the functionality without really exposing much of things that are Windows-only." to quote their reply.
And System.DirectoryServices.AccountManagement on Linux/MacOS will have to wait. You can see the issue is still "Open", and IMO it would be "Closed" if they plan to drop it.
Where have you read the anouncement?