Funny bc I'm not sure we'll called it guimauve in french. Will say it's made out of guimauve and reserve the term guimauve for candy made the same way but with other form and colour.
Also, it's unfortunate that guimauves, including marshmallow, are not gelatinased from marsh mallow roots anymore. It use to be vegan.
So it's not using the idea of "mauve" as in the color in the name but instead the idea of "mallow/malva" as in the plant. In english those ended up being two different words with the same root. The mistletoe actually was originally refering to hibiscus in the latin, but changed. Origin of the confectuary from the marsh mallow plant comes from Ancient Egypt, so this is actually all descended from Latin/Greek