It's a spectrum. If it's really easy to be historically accurate, I support that. If you have to go to great lengths to find someone who looks like the historical figure then it's not worth it.
If you're making a movie about Jesus outside of the region that he came from, the Levant, then no it probably isn't super easy to find a similarly looking person. It's really not a good analogy for several reasons, including the fact that Jesus is portrayed as many different ethnicity's' across the globe for centuries.
If all of these things can be done easily, yes they should. It's also much easier to find an ethnic french women than the points mentioned. Here are her qualifications, which probably hundreds if not thousands of ethnic french qualify for as well.
"She responds to our four criteria -- a resident of Orleans for 10 years, a student in an Orleans high school, and a Catholic who gives her time to others."
I think it's important to respect the ethnic traditions of a region, to a reasonable degree. I can understand why ethnic french would be upset. I don't think it's that hard to see why.
Have all the previous Joan of Arcs been ethnically French?