Are you sure it's the same people? That said, even if it is, there's something to be said for intentionally sharing a constrained set of code vs using something that spies on you in real life.
However. It will eventually, chunk by chunk, upload the full source code of the app you are writing. Complete with all typos and mis-pastes. Like youtube blocks videos with just a hint of copyrighted music, they may be able to detect use of "patented" algos or something like that and block you/ send a lawyer/etc.
Inded, some folks are so worried about their code being sucked up by an AI bot they forget they ship every single revision and byte to MS via github. If MS wanted to be devious with the data entrusted to them they could have done it already.
I suppose it happens, but I suspect the set of people who distrust github/MS enough to not use them for git hosting but still use copilot is quite small.
