They may have done that. It may have made it clearer to them that they were transferring over a lot of trust to someone else, and they might have taken it more seriously and used a different approach. It can be helpful to have more friction for something like this.
That's true, but I have the (perhaps wrong) impression that most people would take handing over control of a signing key more seriously than a repository on GitHub or a package on npm. It very explicitly involves trust / security so it's harder to ignore what should be obvious.