As an open-source developer with a fairly popular project (https://github.com/neuml/txtai - 2.6K+ stars), I'll say GitHub Copilot doesn't concern me but I understand the rationale.
I actually think with some additions it can be beneficial to the open-source community and introduce developers to libraries they couldn't quite articulate a google search for.
For example, one good addition to Copilot and really any generative AI tools would be a method of attribution. Code would be one of the easier ones. When generating a function snippet, add footnotes/citations for the top 3-5 most similar functions in the training database. This can be accomplished with a semantic index over the training set.