I beg to differ. FWIW, I'm a professional UX and Product Designer, and I just went through the process of getting rid of all those sets (which I still don't know how they got there), and the process was
1. Select a song
2. Hit the - button
3. (sometimes, but not always) get the "Are you sure you want to do this?" message
4. Confirm
5. Select next song to delete.
There were over 100 duplicate songs and sets in this one set list. So at least 100 clicks, and really closer to 200 clicks.
With a bulk action, I envision
1. Select song at start of set to delete
2. Select ellipsis menu
3. Select "Delete multiple items"
4. At prompt, select the last item to delete.
5. Confirm.
That is 5 clicks.
Alternatively, in the "View Set List" page,
1. Select check boxes for songs to be deleted
2. Select (from a new menu) "Delete songs"
3. Confirm.
With the ability to shift+click a range, that reduces the number of clicks drastically.