The US is not a region. US East (Northern Virginia) is one region, and US East (Ohio) is another region. There are also other US regions, like US West (Oregon) and US West (Northern California).
If there's confusion about the concept of regions, it seems to be coming from Amazon themselves. They couldn't just call it the Ohio region?
Is that really an issue? Sometimes I get the number suffixes confused (like us-west-1 and us-west-2). Additionally, would you refer to the Sydney region or the New South Wales region?
For people from outside of North America, "us-east-2" is far more informative than "Ohio".