The refinementList widget is indeed designed so that it wont show any facet values that do not have any matches, to prevent the situation where your user selects a filter and does not find any results.
That said, we have a guide for showing facets with no hits here: https://www.algolia.com/doc/guides/building-search-ui/widgets/customize-an-existing-widget/js/?language=js#display-facets-with-no-matches
You can even define the facet values you want to show manually: https://www.algolia.com/doc/guides/building-search-ui/widgets/customize-an-existing-widget/js/?language=js#add-manual-values
The alternative to this is to use a conjunctive facet such as the Hierarchical menu or the Menu widget which will allow your users to select any facet value and ensures that results are being returned by changing the facet value to match the new selection.