Today, for you to be able to use All Clusters you need to have permissions on each project, your user needs to be included in each project.

When we use a federation, we generally don't grant permission for each project to a team of administrators. We grant ORGOWNER, for example. By doing this, we lose access to All Clusters. The idea was to include the permission to use All Clusters for project-level permissions that have permissions to read project resources, for example ORGOWNER or ORGREADONLY.