If this person were stalking you in real life, I would definitely see it as a problem. But the common mistake people seem to make a lot is that the world in the game and real life have anything to do with each other. It's may seem bad but it's about as bad as a pesky gnat at worst.

My advice is just blacklist him (yes I see that you have done that already) and just use him as a punchline is your FC or something like a running gag. Make some humor out of it. "Wow your crazy! I meen like <name of stalker> crazy!" "How often dose <stalker> wash his hands do you think?" stuff like that.