Germany is a broken country, and this illustrates it on a micro-level

It gets worse. These German "Sparkassen" are small to at most medium sized credit unions. They are organised in a larger umbrella organisation that takes care of some of the services like IT, but the individual banks can pick and choose what and how much they want to handle themselves.

Some of them are larger and pretty well organised, but there are also a lot of small ones that just don't have the people and expertise for things like proper IT security practices. But customers trust them, because they position themselves as these local neighbourhood banks, even though most of them are pretty incompetent and will rip you off with high fees on accounts and shitty, underperforming investment products.

It seems to me the better and simpler solution is to continue teaching your users that this pattern this bank engages in is in fact still the pattern of hostile actors and let the bank deal with the consequences.

The system will surely rectify itself eventually when their spammy, manipulative, promotional banker campaigns do not produce results (is that a bad thing?) and they seek out firms that do produce results based on knowing what they are doing.

The author could even use it as an opportunity to promote his or someone else’s services and use this write-up as an artifact of evidence.

I don’t want to get too generalizing, but it is a perspective that does not surprise me coming from what seems to be a German, for better or worse. Complaints about not being in compliance with universal norms instead of taking advantage of a presented opportunity to break ranks for one’s their own individual advantage, strikes me as a very German perspective; like I said, for better or worse, without judgement, since both of these perspectives have their advantages and disadvantages.