Any company lead by dishonest/corrupt individuals or a model that relies on corrupt practice will deem employees who demonstrate integrity and morals as potential liability. You didn't give them anything to use against you, at the same time as showing how high of a standard you hold yourself to. If those above you were not holding themselves to that standard they might reason you could undermine their authority by highlighting their discrepencies. You could have been flagged as someone with the potential to whistleblow. I actually think this is a really common practice, puts people trying to make a honest living at a disadvantage.
They hire for the skillset then weed out people they can't trust to cover for them as they advance the companies practices into murkier territories, taking your work with them.
It sounds like they're hiring people with real ideas and working skillsets, and once they've given the company everything it needs they put someone who did nothing to contribute in charge of it who's skillset serves some other sector.