Because they don’t get listed by browse.feddit.de you’ll want to browse https://kbin.social/magazines to browse “magazines”, which is what they call communities
e.g. !RedditMigration@kbin.social
or directly, https://kbin.social/m/RedditMigration
Why YSK: Federation literally just synched up thanks to the tireless efforts by @ernest@kbin.social over the past few days.
I don’t think it’ll end well for them, and it’s a disappointing choice. However, choosing to not federate is just as much a part of the system as choosing to federate. If everyone had to run exactly the same setup we everyone else, the whole thing would be pointless.