CUDA support for docker containers is provided through the open source Nvidia-Docker project maintained by Nvidia[1]. If anything this is a great argument for NVIDIAs usage of open source.
Searching that project's issues shows that Nvidia-Docker support on MacOS is blocked by the VM used by Docker for Mac(xhyve) not supporting PCI passthrough, which is required for any containers to use host GPU resources.[2]
xhyve has an issue for PCI passthrough, updated a few months ago, which notes that the APIs provided by Apple through DriverKit are insufficient for this use case[3]