"Doesn't that sentence mean, 'If humans have no love and hope, then isn't there no point in saving them?'"
For ordinary people, this might be a natural feeling, but not for a Judge.
Simply put, it's a matter of professional ethics.
For example, just like a criminal who trafficks children, if discovered, everyone would beat them to death. But if they don't die, they'd be taken to a hospital for first aid. Would a doctor give up on treating them because of the heinous acts they've done, and just watch them die?
That's impossible.
A Judge is the same; saving humans is their job, not their mission. The latter requires emotion to sustain, while the former is simply a task to be done.
No matter if humans are good or bad, treacherous or stupid, kind or evil, as long as they are humans, they must be protected.
Of course, if anyone hinders a Judge's work, their only end is death.
