I was referring to life in general if you're ok with people shoplifting and don't understand that someone stopping said thief is just being a good samaritan, being a Marine in this case is virtually irrelevant other than it probably gave him the confidence and ability to stop the person.
Would you be ok with someone coming into your house while your not there taking everything, after all no one got hurt or would you hope that if someone saw it they would stop the thief?