If you're trying to think with your heart you're not going to see anything objectively.
Have a look at nature, for a moment.
How many times in a day does a predator kill other animals?
Why? Personal gain.
What reason does the regular thug have for murdering someone and taking their wallet? Personal gain.
Not evil, law of the jungle, you have to always stay on top.
And don't give me no "he didn't need to kill that person but a predator needs to kill to live" crap, people kill people for desperate reasons.
This thug might have a gambling debt, if he doesn't kill this dude he's dead himself.
His situation pushes him to commit the act, he did it because he needed it.
Human nature, primal instinct. You find it evil, if animals could talk they'd laugh at you.