It is still part of the orthographic rules for Frakturschrift, i.e. not using a long s in fraktur would have been an orthographic mistake. Since Fraktur was use

It is still part of the orthographic rules for Frakturschrift, i.e. not using a long s in fraktur would have been an orthographic mistake. Since Fraktur was used into the 1940s, people were very much used to it.