Trust comes into play when users are denied these freedoms; users have nothing else on which to make an informed decision. Therefore users are left to evaluate promises such as the promises you made. Belief in those promises essentially boils down to uninformed trust. It's no secret that many other proprietors do spy on their users (Microsoft purposefully changed Skype protocol to better allow spying, according to http://www.guardian.co.uk/world/2013/jul/11/microsoft-nsa-co...). I'm pretty sure Microsoft wants to have a good reputation despite their behavior.
As you said in the post you linked to, "Although this is my current mindset, it can change in the future.". This could apply to the promises you made (or strong convictions you posted about on github.com) as well.
The question of maintaining Marta is another issue I think is misstated in your response here and on github.com: with free software users can maintain software too. They could even choose to hire you to do the job. And they can certainly host their own discussions regardless of Marta's license. The underlying issue has to do with whether users will be able to make the software they run on their computers do what they want the software to do (which is the issue with which I raised my first post on this thread) and thus retain control over their computer.