When I used to post on a now defunct forum, there was a Conservatives only room. For many their attitudes changed in suprising ways when not faced with what they perceive as high-fallutin' or unreasonable opposition. And they would be given a sanctuary as it were, equal to the Liberals Only Room. Eveyon's human. I think it would stimulate more activity in the Libs Only Rm. because two opposite rooms would create balance.
Many Libs enjoy posting in NHB and vice-versa for Cons. But without balance, many might eschew the one and only alternative..... Just a suggestion.