I think this is one of the biggest of hive problems and one of the most complex to solve.
There are numerous ways to earn votes and there's always that lucky break when your name gets written down on a curators list and everything you post gets you the daily 3-5 dollars regardless of how good it is or how much engagement it has.
It would always seem unfair for new accounts who aren't earning much now, heck even I sometimes look at people's posts and upvotes enviously which have little to no comments and half of the words are filled with the template advertisement and self biography of themselves.
Although this earlier scenario is different from what you're explaining.
If the person is constantly leaching off hive, selling stake and powering down without any given reason, still putting out low content posts and no engagements then of course those who can should down vote.
That's what the down vote is there for yes?
A bit of a slap on the wrist, a warning and punishment...