Fight slop with slop. Use an AI to review it in excruciating detail and write a lenghty justification for the rejection. Make sure to really hit a couple thousand words.
Maybe getting their own time wasted will teach the submitter about the value of clarity and how it feels to be on the receiving end of a communication with highly asymmetric effort.
Nice, but I suspect the PR submitter will simply reply with their own AI-generated counterpoints. They'll probably come to an agreement to turn both of you into paperclips.
If they resubmit you at least have proof that the conversation is completely braindead and the other side is happy to engage in uprofessional behavior and generally wasting time and resources.
This should be convincing enough even for a non-technical team lead while for the initial PR it might be hard to explain objectively why it's bad.
Maybe getting their own time wasted will teach the submitter about the value of clarity and how it feels to be on the receiving end of a communication with highly asymmetric effort.