This is irrational. It might be a complicated question if the foreign-jurisdiction alternatives were more secure, rather than drastically less secure. But since that's not the case, switching from Google Mail actually gets you the worst of both worlds: a mail service that is materially less secure, operating in a jurisdiction where there are literally no rules preventing USG-level adversaries from exploiting it.
So even though Google has a great track record of keeping hackers from taking over your accounts, the news stories about them cooperating with governments makes them seem less "secure" to some people.
What's weird is when it leads to a fallacy where people trust services that are less verified and tested in terms of security just because there isn't the association with government cooperation.