Post or thread: what you are actually removing
A post is the original submission. A thread is the post plus every comment under it. Removing the post takes the discussion out of public view, because comments hang from it. But if the post has already been deleted and the problem lives in the comments, or the discussion has been cross-posted or quoted elsewhere, a request aimed only at the original post is not enough.
That is why the first step is to map the whole footprint: the post, the problem replies, the poster, the community and every cross-post.