"Their homepage says..."

Is the parent suggesting that no one should bother to read the Terms and Privacy Policy, linked to from the homepage. https://protonmail.com/privacy-policy

Despite the parent's claim, the Privacy Policy says the company may log IP address. Temporarily. Irrespective of any request from local authorities regarding a specific user. IOW, they may log anyone's IP address temporarily regardless of whether the particular user is casuing trouble; they can log IP address for everyone. The policy says they log this data for the purposes of preventing fraud and abuse. The problem for privacy-conscious users is that if they log the data, then that entices authorities to try to successfully request it.

The policy, which imposes no obligations on the company BTW, reads as follows:

"IP Logging: By default, we do not keep permanent IP logs in relation with your use of the Services. However, IP logs may be kept temporarily to combat abuse and fraud, and your IP address may be retained permanently if you are engaged in activities that breach our terms and conditions (spamming, DDoS attacks against our infrastructure, brute force attacks, etc). The legal basis of this processing is our legitimate interest to protect our Services against nefarious activities."

There is nothing that says "By default we do not retain any logs". This clearly states they may be expected to retain IP logs. ("IP logs may be kept temporarily...")

But wait there's more.

"We will only disclose the limited user data we possess if we are instructed to do so by a fully binding request coming from the competent Swiss authorities (legal obligation)."

This clearly states the company may disclose the data they possess, e.g., IP logs collected to combat fraud and abuse, if in response to a request from competent local authorities.

Further down is a curious statement about decrypting messages.

"If a request is made for encrypted message content that we do not possess the ability to decrypt, the fully encrypted message content may be turned over."

Why include a statement such as this, specifically the part that says "that we do not possess the ability to decrypt". The company already specified it may disclose the data it possesses. This further statement suggests there could be some situation where they may have the ability to decrypt some messages. Besides their own communications with customers, why would they ever have encrypted messages that they can decrypt. They could state something like "If the request is made for encrypted communications addressed to us or sent by us, ...", but they do not. As such, their statement must include other messages, too.