Some of the NixOS people tried asking (in, admittedly, a somewhat escalatory and inflammatory way) on the HA forums: the HA founder closed (and hid) the thread, so I don't think they (or Nabu Casa) really care if their deps are OSS or not.
https://community.home-assistant.io/t/consider-to-avoid-addi...
It's worth pointing out that for the time being, all of frenck's packages are still MIT, so there's no current danger. It's totally reasonable (IMO) to request things as a OSS developer that aren't technically license requirements, but equally there's not much you can do if the answer to that is "no" and the use is in the scope of the license.
