But the last two words in your quote are "United States." PBS, like all distributors, licenses content from producers of content--sometimes PBS is the producer

But the last two words in your quote are "United States." PBS, like all distributors, licenses content from producers of content--sometimes PBS is the producer, often it is not--for distribution inside a defined territory. For example, Doctor Who, Red Dwarf, Downton Abbey, and Are You Being Served are all British TV shows licensed by PBS for distribution in the US. PBS can't stream them worldwide same as the BBC can't show some of the content it distributes outside of the United Kingdom.