If they're treating it specifically on “code forge” (because they're after coding use cases), there's lots of interesting information that you won't get by just cloning a repo.
It's not just the current state of the repo, or all commits (and their messages). It's the initial issue (and discussion) that lead to a pull request (and review comments) that eventually gets squashed into a single commit.
The way you code with an agent is a lot more similar to the: issue, comments, change, review, refinement sequence; that you get by slurping the website.
Unfortunately, this kind of scraping seems to inconvenience the host way more than the scraper.
Another tangent: there probably are better behaved scrapers, we just don't notice them as much.