When there are a lot of tracks with the same tags (eg, Morning Musume), the system is like "too many search results, add some filters to narrow it down", but none of the filters are of any use (filter by artist? they're all the same artist. Filter by language? they're all the same language, etc)
if a suggested filter ("artist", "language", etc) only has a single option, we shouldn't even make that suggestion
if we run out of suggested filters, we should show all the tracks, no matter how many tracks that is