They implemented their own way of doing this. They don‘t use PGP. I don‘t know how it exactly works, but it‘s open source, so you can look at it yourself.

Subject lines are also not encrypted, unlike Tutanota.

Safari on iOS supports extensions out of the box. You can just install adguard or something else and won‘t have any ads.

There are also third party browsers, which yes, use WebKit, but also can block ads.

Ich kann verstehen, warum Menschen sowas kaufen, aber ich kann auch absolut verstehen wenn man es sich nicht kaufen will.

Yea, people just apply racism to everything instead of thinking about it for a second.