Could somebody please explain to me why this country is still named after Amerigo Vespucci?

The United States of Roy just doesn't have that historical ring to it .

Would you like a tissue?

I will have to research that. 

Because "Country of some un-named Viking"   just doesn't have the same ring to it- 

The country isn't.  The continent is.  The name of the country is a historical accident.  The Declaration of Independence referred to the "thirteen united States of America."  In that reference, you have a number (thirteen), a description of the relationship (united together in common cause), a description of legal status  (State/country), and the location of these states (America -- or North America if you want to be more specific).  Having given this description in the Declaration of Indepedence), the Articles of Confederation then adopted the name "United States of America" as the style of the organization similar to how 170 years later -- when a global organization was formed it was called the "United Nations."

That's what it was named and it never changed.

Because it is the name that was chosen.

It’s not, that’s a myth.