Bridgy doesn’t scrape anything. It works the same as any other ActivityPub instance, the only difference is that it converts some JSON from one format to another.
It also converts edit and deletion events, so in your scenario it would relay that you want your poem or photo deleted.
This isn’t a web scrapper that reposts content like all the bots reposting Reddit threads to Lemmy. This is a protocol translator between federated networks that speak different languages.
Not entirely sure what you mean by that. It deletes posts in the same way that any other ActivityPub server does, by federating the deletion request.
It’s up to the receiving servers to handle that request and delete the post. You can easily have an ActivityPub native server that doesn’t honor those requests.