And what advertising is that precisely? No data ( emails, passwords, drive files ) were shared with the authorities. So the data is still secure and private.

As far as I can tell they haven't falsely advertised.

I'd give them bonus points for transparency ( publishing how many court ordered subpoenas they receive on a yearly basis ) compared to other companies that don't.

Other companies which are prominent in the privacy/secure email scene face similar issues.

E.g.: https://www.internetsociety.org/blog/2021/03/enough-is-enough-what-happens-when-law-enforcement-bends-laws-to-access-data/

I think you're mixing up anonymity with privacy. It can definitely be more anonymous, but you would need to take steps for that yourself ( Tor, VPN, ... ).