No, they don’t mean Jews religiously. They mean Jewish through heritage, similar to the way many countries do citizenship by birthright rather than birthplace (like the US does). In Hebrew law(?) the birthright is passed down by the mother as prior to genealogy that was a surefire way of proving your parent is who they say they are.
My information is secondhand and any corrections are welcome.
Edit: read below for more accurate information.
Right, what’s ‘Dutch’?