Yes, it may have Terabytes in size but it can be easily compressed to very small size because text is highly compressible and that's a positive point. Even the images of the forum can be compressed in batch if someone makes a batch converter for it.

I believe the forum is mostly based on text based posts/threads and those can be highly compressed by anyone who may then upload the torrent by seeding it and then others who want it to be online can also download it and start seeding it.