You meant a binary blob in your distro's repository, so one that was checked, tested, approved and verified with a hash. Which is wildly different than downloading and running random binaries or scripts for that matter off the internet.
No, it's hardly random, it's an official binary provided the Rust project from an official domain managed by the Rust project. If you don't trust it, then you shouldn't trust the Rust source code either.
In this case, the Google internal course explicitly does not trust that random shell script, even if it came from rust-lang.org, while their internal apt repository is trusted. See https://news.ycombinator.com/item?id=34092187
