The author disagrees with GitHub's use of copyrighted code as training data for their ML-powered Copilot product, citing concerns over unauthorized and unlicensed use of copyrighted work. The author has abandoned GitHub and now hosts their public programming work elsewhere. The issue revolves around the use of copyrighted source code without informing customers of the original license. This raises concerns about the rights of copyright holders and the potential for Copilot to facilitate unauthorized use of copyrighted work.