On the one hand, I agree that paying attention to the spammer is bad; on the other, I do believe there might be some use in publicly stating that such PRs will

On the one hand, I agree that paying attention to the spammer is bad; on the other, I do believe there might be some use in publicly stating that such PRs will never be merged and are frowned upon; hopefully other people reading (many of them likely beginner programmers) will get the message. But there's likely a better way to do the "teaching" without drawing any attention to the perpetrator.