I am going to have this conversation with my Polish lawyer next time we meet for dinner.
Who will tell you that unless you're an extremely valued client of the bank, they're not going to entertain any other proposals.
it appears to me that having Polish citizenship means the government, agencies and courts only recognize that person as a Polish citizen.
You're missing the vital part that while Poland demands you identify yourself as a Polish citizen, the Polish State has no opinion on your dual citizenship. It's not permitted, it's not banned, it's merely dealt with through the obligation for you to identify yourself using a Polish document to the authorities.
However, I don't think they can discriminate against someone born abroad with dual Polish and American citizenship.
There's no discrimination. The law requires you to identify yourself as an American citizen when conducting financial affairs within the Polish banking system. Poland is not breaking any laws by requiring you to do so, because there's no law against holding dual citizenship. The penalties only exist for very specific offences, such as identifying yourself to the Polish authorities using a non-Polish document.
I understand where you're coming from, but Poland has no restriction on holding dual citizenship.
but denying a Polish citizen the right to open an investment account in Poland is plainly discrimination,
There's no such thing as a right to open an investment account.
You'd prefer to share with the Russian Federation or ISIS?
I don't see any harm in sharing information with the Americans, as long as they share information with us. I don't see why Americans should be able to get away with blatant tax evasion in Poland just because they've got Polish citizenship, for instance. The law itself might be insane, but that's an issue for the American people to deal with.
They can press the bank all they want, I am not agreeing to any release.
That's why they won't let you open an account. A basic condition of doing business with a bank here is to agree to the transferring of data. If you don't like it, there are banks in interesting places that won't ask questions.
I'm still waiting for you to outline the parts of the Polish Constitution which prohibits the Polish government from sending your data to the USA.