Well, let's see; can give you some guesses as to why so many think William Hoge and Barbara Hume were from Scotland.
Have you found their memorials on FindAGrave? They are buried in the Old Opequon Cemetery in Virginia. The tombstone says "Born in Scotland." Do you doubt this? I'm kidding, of course.
Take a look at this site; has lots of information with citations for you to mull over.
William Hoge b. 1660 Musselburgh, , Midlothian, Scotland d. Bef 8 ...www.palmspringsbum.org/genealogy/getperson.php?personID=I30
His first wife was Barbara Hume, who was the mother of all his children. William Hoge died before August 8, 1749. On that day his will was filed and recorded in ...
Then, I assume, many take their information from The Family of Hoge by James Hoge Tyler. This book can be found on google books:
The family of Hoge
James Hoge Tyler, James Fulton Hoge - 1927
Or, if you have access to Heritage Quest through your library, the book is found on the Search Books database.
Many seem to take this book as gospel, but I haven't found my Hoge there. Of course, she was a woman and sometimes women get left out.