It was a joke implying that annoying NPCs are ripe candidates for elimination.But why would assassins go for them? In my opinion, they are there to shake the moral compass of Rockford, and to give a reason to punish him for not choosing Colleen.
Although, it doesn't look like Monk needs any particular reason to punish Rockford (targeting the player, of course)
I do agree it's possible E could become a target of Hobbs in certain circumstances.