I personally don't mind the grunt work and don't consider that abuse. Grunt work is either outright useful or a learning experience.
If blacksmiths were academics they would produce a large number of faulty nails. (One might argue the vast majority would be faulty!) I doubt blacksmiths would find that acceptable, but many (if not most) academics don't seem to care too much about quality as long as the paper passes peer review.
A PhD can become abusive when the advisor wants to produce more work when someone has done more than enough for a PhD. At that point they have a full researcher getting paid only a fraction of what they could be.
PhD students are paid less than apprentices last I checked, too. According to this page apprentices are paid roughly 1/3 of what professionals are paid:
https://smallbusiness.chron.com/apprenticeship-pay-15304.htm...
So far, at no point during my PhD was I ever paid 1/3 of what my advisor is, even if you factor in benefits. I haven't even received a raise (to my knowledge), but he has.
Again, ideally a PhD is like an apprenticeship, but my experience suggests that case is rare.