I can only assume that the people having trouble understanding kbin/lemmy are either relatively young, or relatively inexperienced with technology. Basically those people whose online experience really only started in the era of Reddit/Facebook/Twitter/etc. Those of us who were online in the early 2000s are familiar with web forums. Kbin Magazines/Lemmy Communities are basically just web forums that can be interacted with from any kbin or Lemmy instance that's federated. Those of us who are even older and were online in the 90s (or earlier) are familiar with Usenet. Kbin Magazines/Lemmy Communities are basically Usenet newsgroups, with the particular instance you're on essentially the same as your Usenet provider. Or for the really old folks like me, instances are like BBSes that are connected to each other with FidoNet.
It reminds me of people who get confused getting on Discord for the first time, when it's really just a modern incarnation of chat-rooms or IRC. None of these ideas are new, and people were able to figure out these core concepts decades ago.