He didn't want to build a wall completely around the US -- few Americans have ever wanted that -- but by 20th century standards Washington's advice certainly was "isolationist" in urging us to avoid foreign wars and alliances.
For a demographically small and militarily weak nation without a Navy and separated from Europe by the Atlantic Ocean, it was very practical advice at the time just as is a father's admonition to his 4 year old child not to cross the street alone.
However, when we grow up, we quit our childish ways and make our mark upon the world.