Not just popular media. The internet in general seems to assume being 'American' is the default and online communities seem to have a lot more American users than those from other regions (even compared to other places that also speak English).
If you ever want proof... well, go through your YouTube subscriptions and ask yourself how many of the channels are by people from the US. For me the number is about 50-60%.
That's probably got more to do with you hanging out at "American places" due to a language barrier. Many countries that don't speak English have online platforms with vast communities of their own. There are massive social and video platforms in Asia/Europe you probably never heard of.
Russian/European version of Facebook is called "VKonakte". Chinese version of YouTube is called "YouKu", Chinese Facebook is called "Weibo". In those places you will barely find any American users or people that speak a lot of English.
If you ever want proof... well, go through your YouTube subscriptions and ask yourself how many of the channels are by people from the US. For me the number is about 50-60%.