Those were the first two specific forums created due to demand at the time, etc. Before adding unspawn and MasterC to all of Distributions, I was added to LFS as I was the one who pretty much got Mr. Beekmans from LFS to say yes to a forum and Aussie is a Slackware guru so he got Slackware when it was added.
Basically at the time Jeremy wanted a minimum of 2 mods per forum, and jharris was the main dsitro mod, so he was automatically a mod of those two forums. So that is why there are us extras in those two forums, etc.
It probably won't be too long before we add another one to distributions, as its just getting bigger and bigger and harder to handle.