I think I'm it. Should I deactivate?
Deactivate your account? Go away?! Heck NO!!!! You should promote him. Talk about him. Post about him.
I strongly relate with your situation. My top bias group is a Japanese alt idol group called PassCode; and their fandom on KPS is minuscule. I have been on your situation. I have an Official PassCode thread that I update from time to time and that almost nobody visit save for me and one more forum member. I've never thought on having it deleted however. All to the contrary, I keep posting content.
You should keep on supporting your bias. I'd suggest that you recreate Psy's official thread and keep updating it. It's a work of love, it's not for showing off.
EDIT: Make a Psy badge. Even if you alone will have it; it's worth it.