Run a decentralized system akin to a modernized mailing list with a nice UI, where every person accessing the list gets to pick how their view of the list is filtered, choosing from competing filters or creating their own. Filters could be machine-based, competing human-moderator based, whatever.

The doomers and the stans can be talking right alongside each other and never see each other; effectively, the doomer 'site' only exists virtually, as a mutually visible consensus among a subset of the network.