MS scraped GitHub ages ago for CoPilot (possibly including private repos - don't put anything you don't want scraped on there), and I'm sure Anthropic and OpenAI did the same, at least for public repos. Huggingface is just in the news now because they've included an opt-out, which the others have conspicuously avoided.

A solution is to run your own git web server. It is not hard but does require setting up your own server. Will let you restrict access, via an account system, to who you want. It's work: to setup, to maintain, to share.