It's not only about the data, it's about the risk that the US would basically turn off things like tax collection and doctors' visits in the Netherlands as part of (say) a first strike on Greenland.

Sure, the chance is low. But in the current climate people are nervous and it's best not to risk it. The current government has already embarked on a long-term strategy to bring more of critical software infrastructure back in-country, selling the core identity provider software abroad would go directly against current policy.