But since that's just, like, my opinion, man, it might cause editwars further on down the line.
This is the ENTIRE problem with trying to deem what is and what isn't /tg/ related. Since /tg/ is so open to many different topics, there really isn't that much that ISN'T /tg/ related. All that trying to deem what is and what isn't will just result in everything except 40k and drawfag stuff being banned. You trying to deem what is and what isn't related are the problem, not the solution. The only exception is if people try to flood this with something to offset the balance.(i.e. If this suddenly inflated with 5,000+ touhou pics while there is still not even 2,000 other pics is when you should step in and take action.)
If you start trying to police this like a retard early on it will just result in this being a dead project.