This image led to a Facebook discussion about the Federation's diversity or lack thereof:
Only 13? Doesn't the Federation have hundreds of worlds?
They do, but the Enterprise only has representatives from 13 of them.
"But fear not. Some of them have their own ships in Starfleet II, aka Starfleet Jr. Others are free to hitch rides via Starfleet Uber. We make sure all species and races have equal access to the stars."
You're explaining the reasons for my initial comment, which I already knew. But you're not giving us any reason why a fictional universe should be so Anglo-American.
TOS made a point of including people from all different nationalities in it, but they got a little lazy when casting TNG.
However, bigots like Kim Davis aren't welcome in Starfleet, so that's good.
13 whole worlds!
I just think it's funny that Picard would use 13 as the measure of Starfleet's diversity. Like, "The US military has members from 13 (thirteen) countries. The other 183 countries aren't represented, but you can't have everything."
This does raise an interesting point though! Worf was raised on Earth by human parents, and still considered himself Klingon, but I wonder if there are aliens that live on Earth and consider themselves Terrans (people from Earth)? They could have had people like that on the Enterprise too.
Point is that "members from other countries" doesn't mean "citizens of other countries." "From" mean they or their ancestors originally came from elsewhere. Obviously.
For more on Star Trek, see Is Captain Kirk a Conservative? and Miramanee in Star Trek Continues.