ProtonMail is a criminal organization that conducted an illegal hack against a target that ended up being innocent. They were proud of it, so they tweeted they broke the law. When they realized ProtonMail leadership could go to prison over this hack they deleted all evidence. VICE wrote an article about it. I just feel bad for the innocent guy who was mistakenly assaulted by a group of criminal PhD's. ProtonMail can never comment about this because if they did it would result in company employees going to jail for criminal behavior.
ProtonMail was created with NSA/CIA oversight
ProtonMail crowdfunded to "Stay Independent." Then weeks after collecting $500k from average people they sold part of their company to a US firm that has close ties to President Obama. How close? The company that part-owns ProtonMail also has delegates to the UN who were selected by Obama.
ProtonMail Behaves like a CIA/NSA "Honeypot." ProtonMail has an Onion domain that allows users to visit their site using the Tor browser. ProtonMail even has an SSL cert for that onion address even though it's completely unnecessary. When a user makes a new account with ProtonMail on Tor they are re-directed from ProtonMail's ".onion" to ".com" address. This is exactly how CIA honeypots operate.
ProtonMail brags about their Swiss privacy protection but ignores the fact that the Swiss have an information sharing MLAT treaty with the United States. So anything on those Swiss servers is likely also on NSA servers.
ProtonMail doesn't provide true end-to-end encryption. A professor who teaches computer science and cryptography Nadim Kobeissi proved that ProtonMail does not provide end-to-end encryption. ProtonMail has since publicly acknowledged that they can decrypt anyone's encrypted content by obtaining their password/passphrase.
ProtonMail's developers do not use ProtonMail. They would know if the company is corrupt, and their dev's do not use it.
(Part 2, next post)