I said before that Accept should never be used outside of Follow interactions. Want to "accept" something? Introduce a new activity type, AcceptSomething.
But now I am fairly certain that Add and Remove should be avoided too, for similar reasons. They all look the same. To figure out what is happening, you may try to resolve target, but that doesn't help because all collections have either Collection or OrderedCollection type and usually there is no property indicating the purpose of the collection.
Hence, AddToMyCollection is much better than Add.
Add and Remove should only be used for representing side-effects: https://codeberg.org/fediverse/fep/src/branch/main/fep/fc48/fep-fc48.md#activities-and-side-effects
