I don't think the Dutch court has any authority with regards to your US citizenship. It would be a massive breach of national sovereignty if Dutch judges could

I don't think the Dutch court has any authority with regards to your US citizenship. It would be a massive breach of national sovereignty if Dutch judges could strip Americans of their citizenship. They could prevent the Dutch banks transmitting your info, but they can do that regardless of your US citizenship. The likely outcome is the Dutch court refuses to touch it. Even if you win, I don't think they'd touch your citizenship. They'd just refuse to extradite. They don't have to do what the US wants just because the subject is a US citizen. The US is going to be infinitely more interested in preventing this than the Dutch are in allowing it though.