There is (or at least was) an API, AFAIK read-only though. I still don't see why one couldn't combine the API and scrapping to get a full read/write interface going.

Wouldn't that require you to give a random site your login to post on your behalf?

It would. Whether you should is another thing entirely. I'm asking why noone seems to even offer the option?

I can't speak for anyone else, but if it were me, I wouldn't expect anyone to trust me enough to use it, so why bother?

People likely would use it. It's a HN account, not a bank account.

Yes, but they shouldn't.

Even though I have no ill intent and it's just an account on a silly web forum, they shouldn't and it would make me sad if they did.

Some of those are apps. Apps should be fine to use those accounts, as they should not contact anything else than HN and HN's API.

But I guess the only way to be sure is to write one yourself.

MiniHack on iOS let's you post and vote if you login through the app.

Or better: why can't HN developers please work on API? Probably brcause building one takes too much effort.... and they don't see reasons to develop one.