Gotcha. As others have already mentioned it is obtuse. If you end up at the post via your own instance it works but if someone links directly to the canonical post then you get confronted with needing to login. e.g. I see this post as https://mylemmy.win/post/114914, so I can interact just fine whereas if someone sent me the link to https://lemmy.world/post/1194109 (same post, different entry point) I'm stuck.