This is not surprising to me. I will still continue to use ProtonMail. I never signed up because of the "no IP logging" thing. In fact, if I had seen it before I just plain wouldn't have believed it, and still used ProtonMail. But hindsight is 20/20
Same goes for any of the German mail providers like mailbox.org or posteo.de ("We do not save your IP address when you visit or use our website. [...] To protect your privacy and for security reasons, we also delete any potential IP address entries made by local email programs from the email headers. Emails sent using our webmail interface or using email programs therefore contain neither your local nor your public IP address."). If the authorities can prove that they have a legitimate reason to expect them to log the IP addresses, then they must do it. They are all normal companies which need to abide by the law if they want to conduct business.