I'm not exactly clear how to bridge this concern at this time. I have raised concern to the mod team, and we are still discussing how things are going to eventually be deployed in terms of features here on kbin.social.
What I will say is when I go to browse All, I get to look at communities in the Lemmy sphere that I'm not subscribed to. And when I click on the link to the community hosted on a Lemmy instance, I can see previous post history from other users without being subscribed to that community. I can't tell why that's not happening in the reverse for Lemmy users who are coming to our magazine.
Edit to add: I think this means much more of a concern for future instances that will eventually be created that federate here, as opposed to current members of instances who have yet to subscribe to our magazine. So that gives me a little bit of hope since the creation of instances will probably be quite slow at first in the Fediverse.