Americans are taxed on their world wide income, regardless of whether they live in the US or have ever visited it. Children of US citizens living abroad are US citizens by birth, and as such - are tainted with the discriminatory FATCA rules that make them ineligible to receive any services from foreign institutions.
When arriving back to the US, these citizens, and new immigrants, get punished again because all their savings and pensions are taxed according to the draconian PFIC rules, which may cause the unsuspecting honest taxpayers end up paying more taxes than the whole savings accounts.
In the world of global economy, the US puts itself in a severe disadvantage by punishing the newcomers and those who work abroad. The US is the ONLY country in the world taxing its citizens worldwide