There's still valid reason to be concerned here. For example, this implies building a diffusion model based on private data can leak it. If I can generate a whole bunch of prompts like "MRI Joe Biden brain tumor" and 1 out of a million times I get a consistent result, that's unacceptable.
Github Copilot could be leaking private code as well.
It seems the only way they can get an extraction is if a highly duplicated (vs the average) training image is used which is counter to a privacy concern.
Github Copilot could be leaking private code as well.