I think you meant "<My country> is the default on the internet. So unless explicitly mentioned I tend to assume content is geared to a US audience." Because you are American and you tend to visit US-centric sites. No shit.

I am pretty sure 90% of sites visited by Chinese citizens to be hosted in, and tailored towards China.

Also it's not just the Internet being US centric. It's American people being US centric in general, and thus on the Internet make it seem like only US exists. It's more cultural than you think it is.