Writers take famous names and elements of stories, throw in a dash of popular sentiment and their own prejudice, and voila! Historical drama. Shakespeare knew his audience (including a certain Tudor queen) and just did his best to please them. And his best was very good (drama).
You are so right. I know several people who get their “history” from The History Channel, other TV, and movies and then refuse to believe that some other point of view based upon actual research could possibly be correct.
Slightly off topic, but I am highly offended when twits, Martin Sheen as Robert E. Lee and Matt Damon as private Ryan come immediately to mind, are cast in those roles. I guess that’s why they call them actors.