I have asked this question in a couple other locations, and have as yet not received an answer.
@Admin
The creators of a page, get to decide where the content appears, to a degree.
I asked the originator of the page, @SpikeTalon, and this was his response:
@PBuck0145 Not sure, the posts don't show up on my end either. They do for me though on SLUG.
@PBuck0145 I think that the way posts are spread though the site may have changed, in the last week or two. My group Natural History, did seem to have a fairly good profile, and got quite a bit of use then suddenly a few weeks ago, it just sort of disappeared into Limbo, without anything within the group changing.
Recently I see posts to that group appearing in [agnostic.com]