I've asked this before and they said that they are all international sites and no single country owns them therefore it's alright to use them.
Some also claimed that although they are headquartered in the US, they are not made by Americans therefore it's alright to use them.
Why do some people immigrate to the US if they are anti-American?
There is a very common, I could say prevailing, sentiment among immigrants in the USA, of America-bashing. The older the age of entry to the US, the more widespread the criticism of the US. This shouldn’t be much of a surprise, though. Moving from one’s home country anywhere else involves changes and adjustment. When culture and environment is different, one spontaneously perceives it as bad, a very common mindset throughout the world.
After spending some time in America and adjusting to the life and culture there, a change in mindset develops. The immigrant is much more hesitant to openly criticise America in front of Americans (but still feels no restraint while among other immigrants, either his compatriots, or even from other lands). The biggest change happens when immigrant travels to the home country: (s)he is now quite more critical of things at home, which (s)he never noticed before (although this still doesn’t stop them from defending their homeland in America). After a long period of life in America, many immigrants do end up adopting it as their homeland, but remain critical of parts of American culture that they resented before the move.
The force of American cultural influence is quite powerful, though. While many immigrants may never completely adopt their new homeland, and while they will remain critical of various aspects of American culture and life, their children, born and schooled on American soil, will invariably grow up to be typical Americans. The environment and its cultural influences will almost always be far stronger than what parents can do at home. Between the school, the playground, the TV and the internet, the second generation immigrant will almost universally be a typical American.
One thing also needs to be said. There are immigrants who come to America with only one main purpose: to earn more money in order to send back home, and once they build enough for retirement, to return to their homeland and live comfortably on the American pension. Some of those may be very much anti-American. They may have children, but many of them send their American-born children to live with grandparents in their homeland (in order to avoid the inevitable American cultural assimilation). I know of several such cases: educated couples (from West Africa), strongly religious, fiercely anti-American, living in the US, with kids growing up overseas, putting money away, sending money to their homeland, counting years until retirement. From the American (patriotic) perspective, this is probably the kind of immigration that they would most likely want to stop.