Given that the topic of this thread is your feedback against those companies, and that it depends on circumstances changing (being able to prove they aren't a ponzi), I would think you would jump at the chance to show you are trustworthy and fair with your ratings, and that you do intend to change feedback as circumstances change. Being in default trust network doesn't mean everyone trusts you, just that the one person who put you on their list does.
I've already proven that I'm willing to remove feedback by removing feedback from nexusmining. Like I said, I've reached out to der_troll who has simply ignored my PM's. I'm willing to remove that negative feedback, der_troll just has to be willing to do the same and get in touch with me.
Looks like you succeeded in using default trust in order to coerce someone else into removing their negative feedback against you. Good for you. That makes you and CanaryInTheMine look like upstanding people who definitely deserve to be in the default trust network, and certainly doesn't lend any credence to other claims that may or may not be true /s.