The Kbin.social you're seeing isn't the instance it's in, it's the site you're going to.
Like if the page was linking to imgur, you wouldn't see any instance. You would see Imgur.com
Every text-based post is going to say kbin.social unless it's using a direct link to the instance source (in which case you would be going to that instance's site rather than the article as it shows in kbin)
If you hover over the startrek, it will show what instance it's from.
It could be good to add, but basically the instance source isn't shown directly on the feed.
edit: I don't get the downvotes though. The thread was asking why it is the way it is. I'm just explaining how it works, not saying that there isn't a problem with it (also noted a bit further down I do agree it should be added somewhere)