He may have stolen money, no concrete proof has been presented by you or anyone else. Until the mixer company posts a scam accusation you should let it die for now.
I strongly disagree with your assessment (underlined), but I will stop pushing the issue. I would note that I did
ask him about the issue prior to opening up my thread.
IMO, the best way to decide if someone should be accepted into a campaign is to check how good of posts they have been making recently, and how often others will respond to the person's posts.
The problem in the past was that certain people were using the trust system as a weapon, rather than a tool to warn others about scammers, or those who objectively will scam in the future, which affected these people's ability to conduct business, including to join a signature campaign.