Well, one is a small Australian company that make money from providing e-mail as a service, the other being a global company that use behavioral profiling to skew your view of the world.

Fastmail doesn't peak into your emails like Google does with gmail. That is a big improvement.

How do you know?

He obviously doesn't know because he's wrong. Fastmail still analyzes mail for spam and indexes them for search, among other text processing.