I'm expecting evidence to confirm the assumptions of the system. I'm assuming any and all available data would be gathered and analyzed. I assume the MCAS system from top to bottom is riddled with bugs and flaws, designed by committee rather than engineers. There's no reason to trust any line of reasoning from Boeing on this matter, they've already demonstrated their incompetence and are not trustworthy.
You seem to not want the FAA to verify the claims of the system with data. I don't know why that would be undesirable. Even if they only confirm what is being stated about MCAS activation, that data would be valuable and demonstrate that the FAA has at least the competence to gather the data. Publishing the raw data along with their conclusions would allow the public to verify their competence at drawing conclusions.
You assume. If we had the data, we'd know how often the 737 MAX, which has different flight characteristics than other aircraft, was actually in those conditions.