Edit: k, idk why you downvoted me, was trying to show you another sub with an audience directly for this question that you may want to also ask, but k go ahead and downvote me OP.
Didn’t downvote you but it’s probably bc Reddit’s original childfree subreddit is a special kind of toxic hellhole; even for Reddit… which is saying something.
I believe the way that link style works is that it does that only if your instance does not have it locally. Here on the fediverse we need one person to subscribe before it will show up on your local instance correctly
It doesn't appear that that's the case, because people on my instance have subscribed to the comm in question and the link still didn't work. When I formatted the link correctly, it worked. Unless there's an interoperability bug between Lemmy and Mbin, which is certainly possible.