This already exists. Of course, you get plenty of disagreement about who should be on the list.

these exist, but because 'annoying account' is a subjective decision, while 'advertisement url' is an objective decision, it is difficult to create a list with a clear brightline between harassment and disagreement

There is at least one hard-left feminist who ended up on GGAutoblock because Randi Harper just disliked her.

This sounds like the kind of thing that will get abused if widely adopted.

then you could harass people by falsely getting them on a block list.

I'm already on some block lists. I'll run into some journalists who have me blocked. Never interacted with them. I hardly interact with anyone, but some block lists just take the entire list of followers from people and add them.