If they see it they can reject the PR instead of going back and forth with a robot now without any complaints because they can just point to “follow our guidelines”

Without the ability to say “It goes against the guidelines” the annoying robot can tirelessly complain and plead to let its robot code into the codebase. It can keep saying “there are no rules against robot slop contributions” or “there are no rules against using a robot as a medium for conversation” draining more time and energy from a finite pool of people capable of spending time and energy reviewing code and communicating.