That’s a very sad response. We wonder why the world is becoming so cold, untrusting and divisive, now we have a hint. Why would your first response to someone wanting to talk to you be so dismissive? How depressing. It wouldn’t hurt to entertain his request. It wouldn’t take long to figure out his motives. If he just wanted to talk, you might learn something, if he was selling something or was just a jerk you could always end the conversation. Hopefully, politely.
When I was younger, Just sitting in a bus terminal, or waiting at a dock for the launch to take me back to the training ship, I have had people approaching me who were miserable and thinking of suicide. I think I did well. In fact I think one of them actually got Satan pissed at me for saving him.
Sad but that’s the way it is. My response would be based on experience. It’s almost always been a trolling homo, hooker, or scammer who initiated a conversation.