That doesn't mean we don't care about users' needs for protection—on the contrary, we care a lot and help people with these requests every day. No one goes away empty-handed. We just have to use more precise tools than wholesale deletion. These include renaming accounts, retroactively assigning comments to throwaway accounts, deleting specific posts (especially if they don't have replies), redacting specific info from posts, and more.
EDIT: Reading the other responses, it looks like HN will actually do this if you ask. Nice to know! +1 to the request to automate this and provide UI for it for users to self-serve.
I definitely appreciate the idea of there being a community interest in both the creation and archive of the work. The salient question in these times I think is whether it will continue to be possible to safely create public works of this type. This is a social issue beyond the scope of HN, but the drift of users away from public social networks and toward private messaging apps is evidence of a change that's already underway.