Gregory's Server@liaizon I can see the point of being able to do it, but my guess is that it's non-trivial to implement... if you're not following an account, your local #Mastodon instance won't be pulling in (subscribing to?) updates for it.
Putting an account onto a list would need to implicitly do a 'soft follow' if following wasn't required as a precondition, and I can imagine the devs decided it was better to require that be done explicitly.
@kadin I think implementation of a "soft follow" is quite a good idea and something that should exist. It is somewhat there already thru different features implemented in some relays. as an admin I would like to select a list of accounts that my server follows and collects the posts of not for myself but for users on my instance to be able to see without having to do any following. the fact that you gave a "blank slate" when you set up a new instance is quite frustrating.