I'm sorry you feel like this, but it absolutely doesn't mean that. I believe we probably devote more engineering resources to open standards development than any other company, with significant resources given to the mailmaint, calext and jmap working groups at the IETF, not to mention the maintenance of the open-source Cyrus IMAP/JMAP server. I don't know why would do that if we were trying to just keep people captive because it's hard to leave. "Your data belongs to you" is one of our core values: https://www.fastmail.com/company/values/
(You can also read more on our open source and standards work at https://www.fastmail.com/company/open-source/)