it doesn’t matter whether you consider it reasonable, as it’s this way for technical reasons.
when a post or comment are created they are created on the users instance. the users instance then tells the community instance about the new post/comment and the community instance relays (announces) this to other instances that have community subscribers.
the fedilink is an id and reference to the original item. this unique id is known to all servers that know about this comment and it is what is used when updates to the post are distributed. except for the reference to the item on the originating instance, no instance stores information about where to find a specific post/comment on a random other instance.