It’s not just about money. It’s a labor burden and a privacy intrusion. And even if iceblade02 could renounce for free, they then must carry the renounciation cert for the rest of their life and show it to every bank they deal with and hope that no data entry errors trigger data oversharing anyway.
They must renounce to get their human rights back. Because without renouncing, they lose their human right to non-discriminatory treatment on the basis of national origin (article 1 of the Universal Declaration of Human Rights).
But back to money, that annual tax filing accidental Americans must file costs them $300+/year -- accountants do not work for free. It’s effectively a tax on the poor.