Don't know about that one,,,but my experience,,,with many people and friends is it's easier for Americans,,,that's all.
And who can venture a guess anyway what a government is doing with some of these goofy rules and requirements. It's only love after all !!
AND I do know that the Tunisian government does NOT recognize when a Tunisian female is married to a NON Tunisian, NON Islamic person. They default to not recognized. After many years of marriage we have finally got my name on her birth certificate and that was a real drama too.