Sorry, I missed an important sentence.
${All the things I said previously}. And, Google Mail is one of their flagship products.
Most of what is on that ProtonMail page is nonsensical. The claim that is relevant to the discussion here --- that ProtonMail has a "smaller attack surface" and is thus structurally more secure than Google Mail --- assumes significant facts not in evidence.
See downthread for my response to the claim that using a mail services outside the US somehow insulates you from NSA snooping.
Does that make the claims that Protonmail is more secure than Gmail false? - https://protonmail.com/blog/protonmail-vs-gmail-security/