No American unions outside of the USA and Canada?

[Colombian Dan]

Today I took a walk past the US embassy in Bogota Colombia. Camped outside the embassy on the street were a couple of Colombian men, one named Carlos Ernesto Trujillo, a former GM worker at a plant in Bogota [[GM Colombia; Colomotores). These men were apparently injured on the job and subsequently terminated from GM. So after listening to his story it made me think, if GM, Ford, Chrylser etc can conduct business in Colombia without issues, and if the Mormans and Jehova's Witnesses can evangelize without issues, why then are American labor unions absent from organizing outside of the USA and Canada?