Reading means downloading. Downloading is equivalent to making a copy. To make a copy of a copyrighted work, you need a license, unless your activity is fair use. Licenses have terms and conditions that must be followed, such as retaining attribution in all derivative works.

That said, FOSS licenses are non-exclusive. Regarding the original upthread topic of GitHub's copilot training, iirc GitHub's terms and conditions involve granting them a license in order to host your code. Depending what else is in those terms, they may have had the ability to use all hosted code for LLM training through that license, instead of the FOSS licensing on any given Open Source repo. But that would only apply to GitHub/Microsoft, not third party scrapers.