This policy may not scale to the point where I get a large volume of messages from people I have zero interest in engaging with; I wouldn't know, because that's not the case. However, in response to your example message, I might say no more than "That's in my profile" or a one-sentence answer with no followup question or other remarks. If he doesn't take the hint, I can either argue back if I feel like being snarky, or ignore him afterwards.