We also lack fine-grained controls around these things. We don't have a way to say "I never want my post to show up in Lemmy." We don't even have a way to say "I don't want my post to ever show up on the blocked server."
Your solution if you don't want to consent to these things is _limited federation_. Not authorized fetch, but actually allowlisting the servers you talk to.
Because we don't have a way to say/enforce these, your option if you aren't comfortable is to not participate.
2/
This is generally fine!
Do you have an "opt out" to someone sending a Dislike to your post? Should that be added? Maybe, but we don't have the tooling or the norms in place to enforce this.
So if someone built an AP service that added dislike, would you feel a breach of consent if your posts were disliked and this was visible in that service?
Maybe! I'm not saying how you should feel, but I'm saying that at that point your option is to _generally revoke consent_, with some limits.
3/