@Anders Rytter Hansen They should be. (streams) has ActivityPub support.

If you can't connect to someone on Hubzilla, this may have two reasons. Either the URL doesn't work in your case for some reason; then try the Webfinger ID instead, the one with the @s.

Or if you've discovered the channel while looking through some Hubzilla stream instead of somewhere that doesn't run on Zot/Nomad, chances are that this particular channel doesn't have ActivityPub on. At least on Hubzilla, ActivityPub is optional per channel and off by default because it doesn't work too well with nomadic identity.

Oh, and (streams) is at least related to Hubzilla. It isn't a straight Hubzilla fork, though. The actual story behind it is so complicated with another five project names involved that even I don't know the exact line of descendance. Maybe Hubzilla is a direct ancestor, maybe it's rather @mike's private instance(s) which AFAIK never ran vanilla Hubzilla and kept the Red Matrix branding way beyond Hubzilla's 1.0 release.