[akkartik]

Yeah he's not going for accuracy with the nom de guerre. The name is part of his campaign to create a larger-than-life cartoonish character to help the Basque movement. Saying crude things is very much part of it. In that regards the choice of name may not necessarily be progressive and an attempt to identify with the Cagot. (Though I haven't read the book in 20 years.)

Edit: I just remembered the Author's Note at the front of the book saying something like, "With the exception of <three people including Le Cagot>, none of the characters in this book are real -- though they may not know it." Unfortunately Google Books doesn't show that page.