My understanding was that `revanced-patches` contained just that: patches. The patches themselves are applied to the target apps on the end user device, so revanced doesn't need to host prepatched binaries that they don't own the copyright to.

Other moral or legal issues aside, this is a pretty clear abuse of the DMCA as far as I understand it.

No, Revanced only has the patches themselves in the repo, there's zero source code or binary or anything copyright related belonging to Google here, the DMCA is invalid.