But i don't even need your hn password. You create a completely new account on my page. To prove ownership of your account all you have to do is put a key into your public profile which i check via the public hn api. At no point i ask for your hn password.

Sure, it's actually exactly what the domain name suggests. You need an hn account to sign up* and then you can write personal messages to other (signed up) users.

*the registration process requires you to put a key into your public profile, to make sure it's your account. This key can be removed once signup is completed. There is no need of an email and i do not collect any data whatsoever.