I've been working on https://github.com/uroni/hs5 as a replacement with similar goals to early minio. The core is stable at this point, but the user/policy management and the web interface is still in the works.
Looks like you cleanly point out their violation of the AGPL. I wish I were a lawyer with nothing better to do, I'd definitely be suing the MinIO group, there's no way they can cleanly remove the AGPL code outsiders contributed.
I do have a separate AGPL project (see github) where I have nearly all of the copyright and have looked into how one would be able to enforce this in the US at some point and it did look pretty bleak -- it is a civil suit where you have to show damages etc. but IANAL.
I did not like the FUD they were spreading about AGPL at the time since it is a good license for end-user applications.