Just because you use a middle-party (your local instance) to send a post to a remote instance it does not automatically exclude you from being bound to the terms of the remote service - especially if you have been notified of the terms.
If is arguable that follower-only posts and tights scopes are much more limited in how they can be bound to ToS conditions than public posts (as they are email-like)
(tl;dr if you wanna make things legally explicit, the fediverse becomes legally complicated)