so I saw that website, but what’s weird is I can’t access most of them when I try to search for them?

I’ll click communities at the top, switch my filter to all, and then search for specific communities and can’t find them. For example according to this list there is an amateur radio instance (I think that is the right word?). When I click it I am lead to it but it logs me out. When I search for it under communities though I cannot find it.

Am I doing something wrong? Is there something I’m not grasping about this?