C'mon man...thug in the park with a gun, strongarming wallets. That guy is pretty much a terrorist, only lacking the 'politically motivated' label for his crimes. Heck, if he jokingly says "I only rob republicans cuz democrats don't have any money" and it turns up on tape he is a terrorist.
And what does law enforcement say to do if you get mugged? Cooperate. What does society say if you don't cooperate? You're an idiot. What is the mantra we chant anytime the subject comes up? 'Your wallet isn't worth your life!'
So they paid off like a slot machine when they had a kidnapping. That happens all over the world all the time. That's how simple it really is.
It's basically the prisoner's dilemma.