I think this is an absolutely absurd take. A post is the same post no matter who views it - it belongs on the instance where it was posted. Sure it might show up in your timeline or comments somewhere else but for the post itself there should only be one canonical link. If mastodon can't manage to show a simple text post with a small image to anonymous visitors without falling over then it's mastodon that needs to change and not how people interact with it. Most people don't even have a fediverse account ffs.