I think this means that the dead wood (useless/burdensome people or things) are the same anywhere they are. So the useless are useless not only in one situation but useless all around.
Explanation:
Example: He cut the "deadwood" from the group. So he is getting rid of the useless people in the group.
The three rioters swore an oath to kill death but greed took a tow on them and they ended up killing each other because of eight bushels of gold they each wanted for their vices.
