“What stops me from killing a tramp?”
The tramp himself, of course. (Self-defense)
Utter, clueless, nonsense.
The intractability of this problem shows how moral ends, like David Hume said, cannot be deduced. The part within us that says “murderers ought to be punished” is separate from the part that says, “stolen goods ought to be returned.” Righteous vengeance and righteous restitution are separate but equally valid human moral instincts.
We all know in our hearts the tramp-killer needs to go down. Justifying that shouldn’t require tortured reasoning.
Hume’s argument so interpreted is a mere assertion. His actual argument is that as a matter of deduction if facts are not pregnant with values that no deduction will succeed in drawing out of them a value, because a deduction cannot extract more out of the premises than are in them. That’s all his argument leads to. Anything more is ontological commitments he will have to argue.