If we accept motorcar= stands for two-track motor vehicles (maybe the wiki page should be edited to explicitly say that, instead of having it as a parenthetical next to motorcar), then surely motorcycle= also stands for all one-track motor vehicles by the same logic, encompassing motorcycle, moped and mofa. So motorcar=no motorcycle=no would imply mofa=no anyway. And then you have a choice between motorcar=no motorcycle=no mofa=yes or motor_vehicle=no mofa=yes.
Only in Switzerland does anyone try to tag âno motor vehicles except mofasâ as motorcar=no motorcycle=no, AFAIK.