It's ironic that the US charges income tax on Americans earning money while living in a different country when 18th Century Americans really did not like that UK charged them taxes while not living in the UK.

This is the wormhole that later led the the realization. Yes, the early American revolutionaries were upset about "taxation without representation" and this is a little different; living abroad and being taxed nowadays is more like "taxation with representation while living abroad." Anyways, I thought it was interesting to learn that the UK has "residence-based tax" laws.

Edit: Added a sentence to clarify that I am not claiming ex-patriots today are being taxed without representation.