You still need to have the foresight to do things like not reuse usernames, even use your real name, or accidently post something that could identify you. It's still an account owned by a person

I've always thought - if it's possible for someone trawling HN to build a pretty comprehensive profile of users based on usage pattern, comment structure, and occasional personal details shared (like gender, familial status, location).

I think it'd be pretty easy for most accounts that have > 1000 comments.