[Oni]

While it would be easy to set it up, there is a big problem...
If a user connects to a tor hidden service, the server sees it as 127.0.0.1(a.k.a localhost), because everyone would be connecting from the same adress, there would not be a way to tell if a user is using multible accounts and worst of all, because you could not ban an ip, anyone could just come, spam the forum until an admin bans the account, than they could create a new one and repeat the spaming.
Making a tor hidden service for sinister.ly is a horible idea.

That, and it is unnecessary. We allow people to use VPNs/TOR, but there's little reason to operate as a hidden service.

Spoiler:

I personally distrust TOR.