Then why the weak sauce denial from Mastercard? They could have denied much more than they did, and had every incentive to do so, but chose not to rule out allowing anyone acting on their behalf enforcing rules that they wrote, and chose not to deny taking any action in response to social media campaigns they were certainly aware of and were explicitly named in. They offered no explanation as to why they had rules on their books that, according to their statement, they have no business enforcing.

If the crux of the issue is that everyone has arranged a system where nobody has to take responsibility for anything, none of what you’ve said absolves Mastercard (or Visa) of any guilt.